Method and system for transferring dies between surfaces

ABSTRACT

A method, system, and apparatus for a die frame, and for transferring integrated circuit dies therewith, is described. In one aspect for making a die frame, a wafer that comprises a plurality of dies is attached to a surface of a tape structure. A grid of grooves is formed in the wafer to separate the plurality of dies on the surface of the tape structure. A portion of the tape structure that is accessible through the grooves of the grid is caused to harden into a grid shaped structure. The grid shaped structure removably holds the plurality of dies. One or more dies of the plurality of dies can be moved from the grid shaped structure onto a target surface. In an alternative aspect, when the grid of grooves is formed in the wafer to separate the plurality of dies on the surface of the tape structure, the surface of the tape structure is breached in the grooves. The breach causes a hardening material encapsulated in the tape structure to be released and to harden in the grooves into a grid shaped hardened material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/400,101, filed Aug. 2, 2002 (Atty. Dkt. No. 1689.0110000), and is acontinuation in part of U.S. application Ser. No. 10/322,701 (Atty. Dkt.No. 1689.0110003), filed Dec. 19, 2002, which are both hereinincorporated by reference in their entireties.

The following applications of common assignee are related to the presentapplication, and are herein incorporated by reference in theirentireties:

“Method and Apparatus for High Volume Assembly of Radio FrequencyIdentification Tags,” Ser. No. 10/322,467, filed Dec. 19, 2002 (Atty.Dkt. No. 1689.0110001);

“Multi-Barrel Die Transfer Apparatus and Method for Transferring DiesTherewith,” Ser. No. 10/322,718, filed Dec. 19, 2002 (Atty. Dkt. No.1689.0110002); and

“System and Method of Transferring Dies Using an Adhesive Surface,” Ser.No. 10/322,702, filed Dec. 19, 2002 (Atty. Dkt. No. 1689.0110004).

BACKGROUND OF THE INVENTION

1 . Field of the Invention

The present invention relates generally to the assembly of electronicdevices. More particularly, the present invention relates to theassembly of radio frequency identification (RFID) tags.

2. Related Art

Pick and place techniques are often used to assemble electronic devices.Such techniques involve a manipulator, such as a robot arm, to removeintegrated circuit (IC) dies from a wafer and place them into a diecarrier. The dies are subsequently mounted onto a substrate with otherelectronic components, such as antennas, capacitors, resistors, andinductors to form an electronic device.

Pick and place techniques involve complex robotic components and controlsystems that handle only one die at a time. This has a drawback oflimiting throughput volume. Furthermore, pick and place techniques havelimited placement accuracy, and have a minimum die size requirement.

One type of electronic device that may be assembled using pick and placetechniques is an RFID “tag.” An RFID tag may be affixed to an item whosepresence is to be detected and/or monitored. The presence of an RFIDtag, and therefore the presence of the item to which the tag is affixed,may be checked and monitored by devices known as “readers.”

As market demand increases for products such as RFID tags, and as diesizes shrink, high assembly throughput rates for very small die, and lowproduction costs are crucial in providing commercially-viable products.Accordingly, what is needed is a method and apparatus for high volumeassembly of electronic devices, such as RFID tags, that overcomes theselimitations.

SUMMARY OF THE INVENTION

The present invention is directed to methods, systems, and apparatusesfor producing one or more electronic devices, such as RFID tags, thateach include a die having one or more electrically conductive contactpads that provide electrical connections to related electronics on asubstrate.

In aspects of the present invention, a die frame is formed. Furthermore,dies are transferred using the die frame.

In one aspect for making a die frame, a wafer that comprises a pluralityof dies is attached to a surface of a tape structure. A grid of groovesis formed in the wafer to separate the plurality of dies on the surfaceof the tape structure. A portion of the tape structure that isaccessible through the grooves of the grid is caused to harden into agrid shaped structure. The grid shaped structure removably holds theplurality of dies. One or more dies of the plurality of dies can bemoved from the grid shaped structure onto a target surface.

In another aspect for making a die frame, a wafer that comprises aplurality of dies is attached to a surface of a tape structure. The tapestructure comprises an encapsulated hardening material. A grid ofgrooves is formed in the wafer to separate the plurality of dies on thesurface of the tape structure. The surface of the tape structure isbreached in the grooves while forming the grooves to cause theencapsulated hardening material to harden in the grooves into a gridshaped hardened material in the grooves of the grid.

In an aspect, dies may be transferred from a die frame made according tothe present invention. A die frame is positioned closely adjacent to asurface of a substrate such that a die of a plurality of dies removablyheld in the die frame is closely adjacent to the substrate. The die istransferred onto the closely adjacent substrate from the die frame. Eachdie may be transferred from the die frame to the closely adjacentsurface in this manner. Dies may be transferred from the die frame oneby one, or multiple dies may be transferred at a time.

In one aspect, dies may be transferred between surfaces in a “pads up”orientation. When dies are transferred to a substrate in a “pads up”orientation, related electronics can be printed or otherwise formed tocouple contact pads of the die to related electronics of the tagsubstrate.

In an alternative aspect, the dies may be transferred between surfacesin a “pads down” orientation. When dies are transferred to a substratein a “pads down” orientation, related electronics can be pre-printed orotherwise pre-deposited on the tag substrates.

In another aspect, a system for forming a die frame is described. Awafer preparation module applies a wafer to a surface of a tapestructure. The wafer preparation module forms a grid of grooves in thewafer to separate the plurality of dies on the surface of the tapestructure. A hardening agent source causes a portion of the tapestructure that is accessible through the grooves of the grid to hardeninto a grid shaped structure. The grid shaped structure removably holdsthe plurality of dies. One or more dies of the plurality of dies can bemoved from the grid shaped structure onto a target surface.

In still another aspect, another system for forming a die frame isdescribed. A wafer preparation module applies a wafer to a surface of atape structure. The wafer preparation module forms a grid of grooves inthe wafer to separate the plurality of dies on the surface of the tapestructure. The tape structure comprises an encapsulated hardeningmaterial. A wafer singulation module forms a grid of grooves in thewafer to separate the plurality of dies on the surface of the tapestructure. The wafer singulation module breaches the surface of the tapestructure in the grooves when forming the grooves to cause theencapsulated hardening material to harden in the grooves into a gridshaped hardened material

In another aspect of the present invention, a system and apparatusenables the assembly of RFID tags. A die transfer module is present totransfer a plurality of dies from the support surface to the tagsubstrates in either a pads up or down manner

In another aspect of the present invention, an alternative system andapparatus enables the assembly of RFID tags. A wafer preparation moduleis present to transfer the dies from the support surface to a transfersurface. A die transfer module transfers the dies from the transfersurface to the tag substrates in either a pads up or down manner.

These and other advantages and features will become readily apparent inview of the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate the present invention and, togetherwith the description, further serve to explain the principles of theinvention and to enable a person skilled in the pertinent art to makeand use the invention.

FIGS. 1A shows a block diagram of an exemplary RFID tag, according to anembodiment of the present invention.

FIGS. 1B and 1C show detailed views of exemplary RFID tags, according toembodiments of the present invention.

FIGS. 2A and 2B show plan and side views of an exemplary die,respectively.

FIGS. 2C and 2D show portions of a substrate with a die attachedthereto, according to example embodiments of the present invention.

FIG. 3 is a flowchart illustrating a continuous-roll tag assemblyoperation.

FIGS. 4A and 4B are plan and side views of a wafer having multiple diesaffixed to a support surface, respectively.

FIG. 5 is a view of a wafer having separated dies affixed to a supportsurface.

FIG. 6 shows a flowchart providing steps for transferring dies from afirst surface to a second surface, according to embodiments of thepresent invention.

FIG. 7 shows a flowchart providing steps for transferring a plurality ofdies from a first surface to a second surface using an adhesive surface.

FIGS. 8-10 show views of a plurality of dies being transferred from afirst surface to a second surface using an adhesive according to theprocess of FIG. 7.

FIG. 11 is a flowchart illustrating a “pads up” die transfer onto a tagsubstrate.

FIGS. 12A and 12B are plan and side views, respectively, of a pluralityof dies in contact with a support surface and a transfer surface.

FIG. 13 is a view of a plurality of dies attached to a transfer surface.

FIG. 14 is a view of a “pads up” oriented die in contact with a transfersurface and a tag substrate.

FIG. 15 is a view of a “pads up” oriented die attached to a tagsubstrate.

FIG. 16 is a flowchart illustrating a “pads down” die transfer onto atag substrate.

FIG. 17 is a view of a plurality of dies in contact with primary andsecondary transfer surfaces.

FIG. 18 is a view of a plurality of dies attached to a secondarytransfer surface.

FIG. 19 is a view of a “pads down” oriented die in contact with atransfer surface and a tag substrate.

FIG. 20 is a view of a “pads down” oriented die attached to a tagsubstrate.

FIG. 21 shows a flowchart providing steps for transferring a pluralityof dies from a first surface to a second surface using a parallelpunching process, according to embodiments of the present invention.

FIGS. 22-29 show views of a plurality of dies being transferred from afirst surface to a second surface using the punching process of FIG. 21.

FIG. 30 shows a flowchart providing steps for assembling RFID tags,according to embodiments of the present invention.

FIGS. 31-36 show views of a plurality of dies being transferred from achip carrier to a substrate using the punching process of FIG. 30.

FIGS. 37-39 show view of substrate structures that include a pluralityof individual substrates.

FIGS. 40-45 show views of a plurality of dies being transferred from achip carrier to a substrate using the punching process of FIG. 30.

FIGS. 46 and 47 show views of the formation of electrical conductors ona substrate.

FIGS. 48A and 48B show views of an example multi-barrel die transferapparatus, according to an embodiment of the present invention.

FIG. 49 shows a flowchart providing example steps for transferring diesusing a multi-barrel die transfer apparatus, according to an embodimentof the present invention.

FIG. 50 shows a cross-sectional view of a multi-barrel transferapparatus being applied to first surface.

FIGS. 51 and 52 show cross-sectional views of a multi-barrel transferapparatus transferring dies to second surfaces.

FIG. 53 shows a cross-sectional top view of an example barrel with dieinside, according to an embodiment of the present invention.

FIG. 54 is a flowchart illustrating a post processing operation.

FIGS. 55 and 56 are block diagrams of tag assembly devices.

FIGS. 57A and 57B show flowcharts providing steps for making a dieframe, according to example embodiments of the present invention.

FIG. 58-62 show example views of a wafer at different process stepswhile being formed into a die frame, according to embodiments of thepresent invention.

FIG. 63 shows a cross-sectional view of an example die frame, accordingto an embodiment of the present invention.

FIGS. 64A-64C show views of a scribed wafer attached to an adhesivesurface, and held in a wafer frame.

FIGS. 65A and 65B show the scribed wafer of FIGS. 64A-64C with asolidifiable material applied thereto, according to example embodimentsof the present invention.

FIG. 66 shows a flowchart providing example steps for transferring diesusing a die frame, according to an embodiment of the present invention.

FIG. 67 shows a block diagram of dies being transferred from a die frameto a substrate tape, according to an example embodiment of the presentinvention.

FIGS. 68A and 68B show flowcharts providing example steps fortransferring dies using a die frame, according to embodiments of thepresent invention.

FIG. 69 shows a system for transferring dies from a stack of die framesto a substrate structure, according to an example embodiment of thepresent invention.

FIG. 70 shows a block diagram of dies being transferred from a stack ofdie frames into a multi-barrel die transfer apparatus, according to anexample embodiment of the present invention.

FIG. 71 shows a flowchart providing steps for making a die frame,according to an example embodiment of the present invention.

FIGS. 72, 73A, and 73B show views of a wafer having separated diesattached to an adhesive surface of tape structures, according to exampleembodiments of the present invention.

FIG. 74 shows a system for forming a hardened grid in the tape structurethat supports the separated dies shown in FIGS. 71-73, according to anexample embodiment of the present invention.

FIG. 75 shows a die being moved from the hardened grid shown in FIG. 74,according to an example embodiment of the present invention.

FIG. 76 shows a flowchart providing steps for making a die frame,according to an example embodiment of the present invention.

FIG. 77 shows a wafer attached to an adhesive surface of a tapestructure that includes an encapsulated hardening material, according toan example embodiment of the present invention.

FIG. 78 shows a laser being used to separate dies of the wafer of FIG.77 and to cause the encapsulated hardening material to harden, accordingto an example embodiment of the present invention.

FIG. 79 shows a perspective view of a saw being used to separate dies ofa portion of the wafer of FIG. 77 and to cause the encapsulatedhardening material to harden into a die frame, according to an exampleembodiment of the present invention.

FIG. 80 shows a perspective view of a portion of the wafer of FIG. 77that has been separated on the tape structure, with a die frame formedby the encapsulated hardening material, according to an exampleembodiment of the present invention.

FIG. 81 shows a die frame formed by an encapsulated hardening materialthat has been detached from a tape structure, according to an exampleembodiment of the present invention.

The present invention will now be described with reference to theaccompanying drawings. In the drawings, like reference numbers generallyindicate identical, functionally similar, and/or structurally similarelements. The drawing in which an element first appears is indicated bythe leftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides improved processes and systems forassembling electronic devices, including RFID tags. The presentinvention provides improvements over current processes. Conventionaltechniques include vision-based systems that pick and place dies one ata time onto substrates. The present invention can transfer multiple diessimultaneously. Vision-based systems are limited as far as the size ofdies that may be handled, such as being limited to dies larger than 600microns square. The present invention is applicable to dies 100 micronssquare and even smaller. Furthermore, yield is poor in conventionalsystems, where two or more dies may be accidentally picked up at a time,causing losses of additional dies.

The present invention provides an advantage of simplicity. Conventionaldie transfer tape mechanisms may be used by the present invention.Furthermore, much higher fabrication rates are possible. Currenttechniques process 5-8 thousand units per hour. The present inventioncan provide improvements in these rates by a factor of N. For example,embodiments of the present invention can process dies 5 times as fast asconventional techniques, at 100 times as fast as conventionaltechniques, and at even faster rates. Furthermore, because the presentinvention allows for flip-chip die attachment techniques, wire bonds arenot necessary.

Elements of the embodiments described herein may be combined in anymanner. Example RFID tags are described in the section below. Assemblyembodiments for RFID tags are described in the next section. Furtherprocessing processes are then described, followed by a description oftag assembly systems.

1.0 RFID Tag

The present invention is directed to techniques for producing electronicdevices, such as RFID tags. For illustrative purposes, the descriptionherein primarily relates to the production of RFID tags. However, thedescription is also adaptable to the production of further electronicdevice types, as would be understood by persons skilled in the relevantart(s) from the teachings herein.

FIG. 1A shows a block diagram of an exemplary RFID tag 100, according toan embodiment of the present invention. As shown in FIG. 1A, RFID tag100 includes a die 104 and related electronics 106 located on a tagsubstrate 116. Related electronics 106 includes an antenna 114 in thepresent example. FIGS. 1B and 1C show detailed views of exemplary RFIDtags 100, indicated as RFID tags 100 a and 100 b. As shown in FIGS. 1Band 1C, die 104 can be mounted onto antenna 114 of related electronics106. As is further described elsewhere herein, die 104 may be mounted ineither a pads up or pads down orientation.

RFID tag 100 may be located in an area having a large number or pool ofRFID tags present. RFID tag 100 receives interrogation signalstransmitted by one or more tag readers. According to interrogationprotocols, RFID tag 100 responds to these signals. Each responseincludes information that identifies the corresponding RFID tag 100 ofthe potential pool of RFID tags present. Upon reception of a response,the tag reader determines the identity of the responding tag, therebyascertaining the existence of the tag within a coverage area defined bythe tag reader.

RFID tag 100 may be used in various applications, such as inventorycontrol, airport baggage monitoring, as well as security andsurveillance applications. Thus, RFID tag 100 can be affixed to itemssuch as airline baggage, retail inventory, warehouse inventory,automobiles, compact discs (CDs), digital video disks (DVDs), videotapes, and other objects. RFID tag 100 enables location monitoring andreal time tracking of such items.

In the present embodiment, die 104 is an integrated circuit thatperforms RFID operations, such as communicating with one or more tagreaders (not shown) according to various interrogation protocols.Exemplary interrogation protocols are described in U.S. Pat. No.6,002,344 issued Dec. 14, 1999 to Bandy et al. entitled System andMethod for Electronic Inventory, and U.S. patent application Ser. No.10/072,885, filed on Feb. 12, 2002, both of which are incorporated byreference herein in its entirety. Die 104 includes a plurality ofcontact pads that each provide an electrical connection with relatedelectronics 106.

Related electronics 106 are connected to die 104 through a plurality ofcontact pads of IC die 104. In embodiments, related electronics 106provide one or more capabilities, including RF reception andtransmission capabilities, sensor functionality, power reception andstorage functionality, as well as additional capabilities. Thecomponents of related electronics 106 can be printed onto a tagsubstrate 116 with materials, such as conductive inks. Examples ofconductive inks include silver conductors 5000, 5021, and 5025, producedby DuPont Electronic Materials of Research Triangle Park, N.C. Othermaterials or means suitable for printing related electronics 106 ontotag substrate 116 include polymeric dielectric composition 5018 andcarbon-based PTC resistor paste 7282, which are also produced by DuPontElectronic Materials of Research Triangle Park, N.C. Other materials ormeans that may be used to deposit the component material onto thesubstrate would be apparent to persons skilled in the relevant art(s)from the teachings herein.

As shown in FIGS. 1A-1C, tag substrate 116 has a first surface thataccommodates die 104, related electronics 106, as well as furthercomponents of tag 100. Tag substrate 116 also has a second surface thatis opposite the first surface. An adhesive material or backing can beincluded on the second surface. When present, the adhesive backingenables tag 100 to be attached to objects, such as books and consumerproducts. Tag substrate 116 is made from a material, such as polyester,paper, plastic, fabrics such as cloth, and/or other materials such ascommercially available Tyvec®.

In some implementations of tags 100, tag substrate 116 can include anindentation or “cell” (not shown in FIGS. 1A-1C) that accommodates die104. An example of such an implementation is included in a “pads up”orientation of die 104, as is further described elsewhere herein.

FIGS. 2A and 2B show plan and side views of an example die 104. Die 104includes four contact pads 204 a-d that provide electrical connectionsbetween related electronics 106 and internal circuitry of die 104. Notethat although four contact pads 204 a-d are shown, any number of contactpads may be used, depending on a particular application. Contact pads204 are made of an electrically conductive material during fabricationof the die. Contact pads 204 can be further built up if required by theassembly process, by the depostion of additional and/or other materials,such as gold and solder flux. Such post processing, or “bumping,” willbe known to persons skilled in the relevant arts.

FIG. 2C shows a portion of a substrate 116 with die 104 attachedthereto, according to an example embodiment of the present invention. Asshown in FIG. 2C, contact pads 204 a-d of die 104 are coupled torespective contact areas 210 a-d of substrate 116. Contact areas 210 a-dprovide electrical connections to related electronics 106. Thearrangement of contact pads 204 a-d in a rectangular shape allows forflexibility in attachment of die 104 to substrate 116, and goodmechanical adherement. This arrangement allows for a range of tolerancefor imperfect placement of IC die 104 on substrate 116, while stillachieving acceptable electrical coupling between contact pads 204 a-dand contact areas 210 a-d. For example, FIG. 2D shows an imperfectplacement of IC die 104 on substrate 116. However, even though IC die104 has been improperly placed, acceptable electrical coupling isachieved between contact pads 204 a-d and contact areas 210 a-d.

Note that although FIGS. 2A-2D show the layout of four contact pads 204a-d collectively forming a rectangular shape, greater or lesser numbersof contact pads 204 may be used. Furthermore, contact pads 204 a-d maybe laid out in other shapes in embodiments of the present invention.

2.0 RFID Tag Assembly

The present invention is directed to continuous-roll assembly techniquesand other techniques for assembling tags, such as RFID tag 100. Suchtechniques involve a continuous web (or roll) of the material of the tagantenna substrate 116 that is capable of being separated into aplurality of tags. As described herein, the manufactured one or moretags can then be post processed for individual use. For illustrativepurposes, the techniques described herein are made with reference toassembly of RFID tag 100. However, these techniques can be applied toother tag implementations and other suitable devices, as would beapparent to persons skilled in the relevant art(s) from the teachingsherein.

The present invention advantageously eliminates the restriction ofassembling electronic devices, such as RFID tags, one at a time,allowing multiple electronic devices to be assembled in parallel. Thepresent invention provides a continuous-roll technique that is scalableand provides much higher throughput assembly rates than conventionalpick and place techniques.

FIG. 3 shows a flowchart 300 with example steps relating tocontinuous-roll production of RFID tags 100, according to exampleembodiments of the present invention. FIG. 3 shows a flowchartillustrating a process 300 for assembling tags 100. Process 300 beginswith a step 302. In step 300, a wafer 400 having a plurality of dies 104is produced. FIG. 4A illustrates a plan view of an exemplary wafer 400.As illustrated in FIG. 4A, a plurality of dies 104 are arranged in aplurality of rows 402 a-n.

In a step 304, wafer 400 is applied to a support surface 404. Supportsurface 404 includes an adhesive material to provide adhesiveness. Forexample support surface 404 may be an adhesive tape that holds wafer 400in place for subsequent processing. FIG. 4B shows an example view ofwafer 400 in contact with an example support surface 404.

In a step 306, the plurality of dies 104 on wafer 400 are separated. Forexample, step 306 may include scribing wafer 400 according to a process,such as laser etching. FIG. 5 shows a view of wafer 400 having exampleseparated dies 104 that are in contact with support surface 404. FIG. 5shows a plurality of scribe lines 502 a-l that indicate locations wheredies 104 are separated.

In a step 308, the plurality of dies 104 are transferred from supportsurface 404 to tag substrate 116. In an embodiment, step 308 may allowfor “pads down” transfer. Alternatively, step 308 may allow for “padsup” transfer. As used herein the terms “pads up” and “pads down” denotealternative implementations of tags 100. In particular, these termsdesignate the orientation of connection pads 204 in relation to tagsubstrate 116. In a “pads up” orientation for tag 100, die 104 istransferred to tag substrate 116 with pads 204 a-204 d facing away fromtag substrate 116. In a “pads down” orientation for tag 100, die 104 istransferred to tag substrate 116 with pads 204 a-204 d facing towards,and in contact with tag substrate 116. An example of step 308 involving“pads up” transfer is described in greater detail herein with referenceto FIG. 11. An example of step 308 involving “pads down” transfer isdescribed in greater detail herein with reference to FIG. 16.

In a step 310, post processing is performed. During step 310, assemblyof RFID tag(s) 100 is completed. Step 310 is described in further detailbelow with reference to FIG. 54.

2.1 Die Transfer Embodiments

Step 308 shown in FIG. 3, and discussed above, relates to transferringseparated dies from a support surface to a tag substrate. The separateddies that are attached to the support surface (e.g., as shown in FIG. 5)can be transferred to the tag substrate by a variety of techniques.Conventionally, the transfer is accomplished using a pick and placetool. The pick and place tool uses a vacuum die collet controlled by arobotic mechanism that picks up the die from the support structure by asuction action, and holds the die securely in the die collet. The pickand place tool deposits the die into a die carrier or transfer surface.For example, a suitable transfer surface is a “punch tape” manufacturedby Mulbauer, Germany. A disadvantage of the present pick and placeapproach is that only one die at a time may be transferred. Hence, thepresent pick and place approach does not scale well for very highthroughput rates.

The present invention allows for the transfer of more than one die at atime from a support surface to a transfer surface. In fact, the presentinvention allows for the transfer of more than one die between any twosurfaces, including transferring dies from a support surface to anintermediate surface, transferring dies between multiple intermediatesurfaces, transferring dies between an intermediate surface and thefinal substrate surface, and transferring dies directly from a supportsurface to the final substrate surface.

FIG. 6 shows a flowchart 600 providing steps for transferring dies froma first surface to a second surface, according to embodiments of thepresent invention. Structural embodiments of the present invention willbe apparent to persons skilled in the relevant art(s) based on thefollowing discussion. These steps are described in detail below.

Flowchart 600 begins with step 602. In step 602, a plurality of diesattached to a support surface are received. For example, the dies aredies 104, which are shown attached to a support surface 404 in FIG. 4A.The support surface can be a “green tape” as would be known to personsskilled in the relevant art(s).

In step 604, the plurality of dies are transferred to a subsequentsurface. For example, dies 104 may be transferred according toembodiments of the present invention. For example, the dies may betransferred by an adhesive tape, a punch tape, a multi-barrel transportmechanism and/or process, or a die frame, such as are further describedbelow, and may be transferred by other mechanisms and processes, or bycombinations of the mechanisms/processes described herein. Inembodiments, the subsequent surface can be an intermediate surface or anactual final substrate. For example, the intermediate surface can be atransfer surface, including a “blue tape” as would be known to personsskilled in the relevant art(s). When the subsequent surface is asubstrate, the subsequent surface may be a substrate structure thatincludes a plurality of tag substrates, or may be another substratetype.

In step 606, it is determined whether the subsequent surface is a finalsurface. If the subsequent surface is a substrate to which the dies aregoing to be permanently attached, the process of flowchart 600 iscomplete. Thus, as shown in FIG. 6, the process proceeds to step 310 offlowchart 300, as shown in FIG. 3. If the subsequent surface is not afinal surface, then the process proceeds to step 604, where theplurality of dies are then transferred to another subsequent surface.Steps 604 and 606 may be repeated as many times as is required by theparticular application.

Any of the intermediate/transfer surfaces and final substrate surfacesmay or may not have cells formed therein for dies to reside therein.Various processes described below may be used to transfer multiple diessimultaneously between first and second surfaces, according toembodiments of the present invention. In any of the processes describedherein, dies may be transferred in either pads-up or pads-downorientations from one surface to another.

The die transfer processes described herein include transfer using anadhesive surface, a parallel die punch process, a multi-barrel diecollect process, a die frame, and a die support frame. Elements of thedie transfer processes described herein may be combined in any way, aswould be understood by persons skilled in the relevant art(s). These dietransfer processes, and related example structures for performing theseprocesses, are further described in the following subsections.

2.1.1 Die Transfer Using an Adhesive Surface

According to an embodiment of the present invention, an adhesivesubstance coated onto a second surface may be pressed against separateddie that reside on a first surface, causing the die to attach to theadhesively coated second surface. The second surface may be moved awayfrom the first surface, to carry the attached die away from the firstsurface. The die can then be transferred to subsequentintermediate/transfer surfaces, or to a final surface, such as asubstrate.

FIG. 7 shows a flowchart 700 providing steps for transferring aplurality of dies from a first surface to a second surface using anadhesive surface. For illustrative purposes, flowchart 700 will bedescribed in reference to FIGS. 8-10, although the process of flowchart700 is not limited to the structures shown in FIGS. 8-10.

Flowchart 700 begins with step 702. In step 702, the second surface ispositioned to be closely adjacent to the first surface that has aplurality of dies attached thereto. For example, as shown in FIG. 8, aplurality of dies 104 are attached to a first surface 802. A secondsurface 804 is positioned closely to first surface 802. In embodiments,for example, surface 802 may be a scribed wafer or support surface, ormay be an intermediate surface. Furthermore, second surface 804 may bean intermediate or transfer surface, or may be a substrate surface. Anexample support surface is shown in FIG. 4A, as support surface 404.Second surface 804 may be a green tape or a blue tape, as they are knownin the industry, for example.

In step 704, a distance between the first surface and a second surfaceis reduced until the plurality of dies contact the second surface andattach to the second surface due to an adhesiveness of the secondsurface. An example of this is shown in FIG. 9. As shown in FIG. 9,second surface 802 is in contact with plurality of dies 104. Either orboth of first and second surfaces 802 and 804 may be moved to cause thecontact. Note that second surface 804 may have the adhesiveness becauseit is an adhesive tape, or may be a surface that has an adhesivematerial, such as an epoxy, glue, or wax applied thereto, to cause it tobe adhesive.

In step 706, the first surface and second surface are moved apart,whereby the plurality of dies remain attached to the second surface. Forexample, this is illustrated in FIG. 10. As shown in FIG. 10, firstsurface 802 and second surface 804 have been moved apart, and theplurality of dies 104 remain attached to second surface 804. Theplurality of dies 104 are detached from first surface 802. The pluralityof dies 104 remain attached to second surface 804 due to a greateradhesiveness of second surface 804 relative to first surface 802.

In an embodiment, flowchart 700 may include the additional step where anadhesive material is applied to the second surface so that theadhesiveness of the second surface is greater than that of the firstsurface.

Note that overlapping (including identical) means may be used to performsteps 704 and 706 to reduce the distance between the first and secondsurfaces, and to move the first and second surfaces apart, or differentmeans may be used. For example, the means used for performing steps 704and/or 706 may include the use of rollers, piston-type punchingtechniques, air jets, and/or any other suitable mechanisms describedelsewhere herein or otherwise known.

Note that flowchart 700 is applicable to dies being oriented in apads-up or pads-down orientation on either of first and second surfaces802 and 804. For example, flowchart 700 may include the further stepwhere the plurality of dies attached to the first surface are orientedso that at least one contact pad of each die of the plurality of dies isfacing away from the first surface. Hence, when the first surface andsecond surface are moved apart, the plurality of dies will remainattached to the second surface in a pads-down manner. Alternatively,flowchart 700 can include the step where the plurality of dies attachedto the first surface are oriented so that at least one contact pad ofeach die of the plurality of dies is facing towards the first surface.Hence, when the first surface and second surface are moved apart, theplurality of dies remain attached to the second surface in a pads-upmanner.

In embodiments, the process of flowchart 700 may be implemented on anyportion of, or all of the separated die on the first surface. Forexample, this process may be accomplished in one or more iterations,using one or more strips of an adhesive coated second surface 804 thateach adhere to and carry away a single column of die 104 from firstsurface 802. Alternatively, a sheet sized adhesive coated second surface804 may be used to adhere to and carry away multiple columns/any sizearray of die 104 from first surface 802.

The following two subsections are presented herein to provide moredetailed examples of die transfer using an adhesive surface, forillustrative purposes. However, the present invention is not limited tothese examples.

2.1.1.1 Pads Up Transfer

As described herein with reference to FIG. 3, in step 308, dies 104 canbe transferred from support surface 404 to tag substrate 116 in a “padsup” manner. When a die 104 is transferred to tag substrate 116 in thismanner, it is oriented so that connecting pads 204 a-d face away fromtag substrate 116.

FIG. 11 is a flowchart illustrating performance of step 308 in greaterdetail for “pads up” transfer. This performance begins with a step 1102.In step 1102, one or more dies 104 are oriented for “pads up” transferfrom support surface 404 onto tag substrate 116. Step 1102 is describedin greater detail with reference to FIGS. 12A, 12B, 13, 14, and 15,which provide exemplary views of dies 104, support surface 404, atransfer surface 1202, and tag substrate 116 during various stages of a“pads up” transfer operation.

Step 1102 comprises transferring die(s) 104 onto a transfer surface.Thus, step 1102 includes steps 1120 and 1122. In step 1120, die(s) 104are placed in contact with transfer surface 1202. A performance of thisstep is illustrated in FIGS. 12A and 12B, which provide views of a die104 in contact with support surface 404 and transfer surface 1202.Transfer surface 1202 is an adhesive material, such as tape. Placingdie(s) 104 in contact with transfer surface 1202 can include the step ofreducing the physical separation between support surface 404 andtransfer surface 1202 until die 104 contacts transfer surface 1202. Thiscan be performed through the use of rollers, piston-type punchingtechniques, and/or air jets.

Step 1120 further includes the step of aligning transfer surface 1202with one or more rows 402. For example, FIG. 12A shows transfer surface1202 aligned with row 402 a. In this example, transfer surface 1202 hasa width 1204 that is selected to contact a single row 402 of dies 104.However, other widths 1202 can be employed that enable contact withmultiple rows 402.

In step 1122, die(s) 104 are removed from support surface 404, therebyresulting in the transfer of die(s) 104 from support surface 404 totransfer surface 1202. FIG. 13 is a view of a plurality of dies 104transferred to transfer surface 1202. Removal of die(s) 104 from supportsurface 404 can include the steps of providing a stronger adhesive ontransfer surface 1202 than on support surface 404, and increasing thephysical separation between support surface 404 and transfer surface1202. Alternatively, removal of dies 104 from support surface 404 caninclude the steps of providing a release adhesive on support surface 404that loses its adhesive properties upon a release action, such asexposure to thermal energy, radiation, or ultraviolet light, andcreating a release action at a time when removal is desired.

After performance of 1102, a step 1104 is performed. In step 1104, anadhesive is applied to tag substrate 116. This adhesive will provide abond between die 104 and tag substrate 116.

A step 1106 follows step 1104. In step 1106, die(s) 104 are transferredonto tag substrate 116 in a “pads up” manner. Step 1106 includes thesteps of placing die(s) 104 in contact with tag substrate 116 andremoving die(s) 104 from transfer surface 1202. Snapshots from aperformance of step 1106 are illustrated in FIGS. 14 and 15.

FIG. 14 shows a die 104 n in contact with a transfer surface 1202 andtag substrate 116. Die 104 n is in contact with a cell or indentation1402 that is formed on tag substrate 116. Indentation 1402 enablesconnection pads 204 to be substantially even with surface(s) on tagsubstrate 116 that accommodate related electronics 106. Placing die(s)104 in contact with tag substrate 116 includes the step of reducing thephysical separation between transfer surface 1202 and tag substrate 116until die 104 contacts tag substrate 116. This can be performed throughthe use of rollers, piston-type punching techniques, and/or air jets. Inaddition, placing die(s) 104 in contact with tag substrate 116 in a“pads up” orientation includes the step of aligning die(s) 104 withcorresponding indentations 1402.

Removal of die(s) 104 from transfer surface 1202 can include the stepsof providing a stronger adhesive on tag substrate 116 than on transfersurface 1202, and increasing the physical separation between transfersurface 1202 and tag substrate 104. Alternatively, removal of dies 104from support surface 404 can include the steps of providing a releaseadhesive on transfer surface 1202 that loses it adhesive properties upona release action, such as exposure to thermal energy, radiation, orultraviolet light, and creating a release action at a time when removalis desired.

FIG. 15 shows a die 104 n released from transfer surface 1202 andtransferred to tag substrate 116. As illustrated in FIG. 15, pads 204are substantially even with surfaces 1502 and 1504 of tag substrate 116,thereby enabling electrical connections to be easily formed between pads204 and related electronics 106 printed on these surfaces.

After step 1106, a step 1108 is performed. In step 1108, relatedelectronics 106 are printed on tag substrate 116. Step 1106 can comprisethe steps of printing related electronics 106 onto tag substrate 116through a screen printing process, an ink jet process, and/or a thermalspray process. Alternatively, step 1106 can comprise the step ofremoving conductive material already disposed on tag substrate 116through an oblation process.

After step 1108, a step 1110 is performed. In step 1110, an overcoatingis applied on tag substrate 116. This overcoating protects elements oftag 100, such as die 104 and related electronics 106, from mechanicalforces. In addition, this overcoating provides electrical insulation.Moreover, this overcoating can provide a compression force on tagsubstrate 116 to further ensure proper connections between relatedelectronics 106 and die 104. Such a compression force can be providedthrough the use of heat shrinkable materials.

2.1.1.2 Pads Down Transfer

As described herein with reference to FIG. 3, in step 308, dies 104 canbe transferred from support surface 404 to tag substrate 116 in a “padsdown” manner. When a die 104 is transferred to tag substrate 116 in thismanner, it is oriented so that connecting pads 204 a-d face towards tagsubstrate 116.

FIG. 16 is a flowchart illustrating a performance of step 308 in greaterdetail for “pads down” transfer. This performance begins with a step1602. In step 1602, one or more dies 104 are oriented for pads downtransfer from support surface 404 onto tag substrate 116. Step 1602 isdescribed in greater detail with reference to FIGS. 12A, 12B, 13-15, and17-20. These drawings provide exemplary views of dies 104, supportsurface 404, a transfer surface 1202, a secondary transfer surface 1702,and tag substrate 116 during various stages of a “pads down” transferoperation.

Step 1602 comprises a step 1620 of transferring die(s) 104 onto aprimary transfer surface and a step 1622 of transferring die(s) 104 ontoa secondary transfer surface.

In step 1620, die(s) 104 are placed in contact with transfer surface1202 and removed from support surface 404, thereby resulting in thetransfer of die(s) 104 from support surface 404 to transfer surface1202.

FIGS. 12A and 12B provide views of a die 104 in contact with supportsurface 404 and transfer surface 1202. Transfer surface 1202 is anadhesive material, such as tape. Placing die(s) 104 in contact withtransfer surface 1202 can include the step of reducing the physicalseparation between support surface 404 and transfer surface 1202 untildie 104 contacts transfer surface 1202. This can be performed throughthe use of rollers, piston-type punching techniques, and/or air jets.

FIG. 13 is a view of a plurality of dies 104 removed from supportsurface 404 and transferred to transfer surface 1202. Removal of die(s)104 from support surface 404 can include the steps of providing astronger adhesive on transfer surface 1202 than on support surface 404,and increasing the physical separation between support surface 404 andtransfer surface 1202. Alternatively, removal of dies 104 from supportsurface 404 can include the steps of providing a release adhesive onsupport surface 404 that loses it adhesive properties upon a releaseaction, such as exposure to thermal energy, radiation, or ultravioletlight, and creating a release action at a time when removal is desired.

After step 1620, a step 1622 is performed. In step 1622, die(s) 104 aretransferred from transfer surface 1202 onto secondary transfer surface1702. In step 1622, die(s) 104 are placed in contact with secondarytransfer surface 1702. FIG. 17 provides an exemplary view of suchcontact, where die(s) 104 are in contact with transfer surface 1202 andsecondary transfer surface 1702. Placing die(s) 104 in contact withsecondary transfer surface 1702 can include the step of reducing thephysical separation between support surface 404 and transfer surface1202 until die 104 contacts transfer surface 1202. This can be performedthrough the use of rollers, piston-type punching techniques, and/or airjets.

Next, pursuant to step 1622, die(s) 104 are removed from transfersurface 1202 to complete the transfer to secondary transfer surface1702. FIG. 18 is a view of a die 104 that has been removed from transfersurface 1202, and is therefore transferred to secondary transfer surface1702. As described herein, both transfer surface 1202 and secondarytransfer surface 1702 are adhesive surfaces. Thus, removal of die(s) 104from transfer surface 1202 can include the steps of providing a strongeradhesive on secondary transfer surface 1702 than on transfer surface1202, and increasing the physical separation between transfer surface1202 and secondary transfer surface 1702. Alternatively, removal ofdie(s) 104 from transfer surface 1202 can include the steps of providinga release adhesive on transfer surface 1202 that loses it adhesiveproperties upon a release action, such as exposure to thermal energy,radiation, or ultraviolet light, and creating a release action at a timewhen removal is desired.

In step 1604, related electronics 106 are printed onto tag substrate116. Step 1604 can comprise the steps of printing related electronics106 onto tag substrate 116 through a screen printing process, an ink jetprocess, and/or a thermal spray process. Alternatively, step 1604 cancomprise the step of removing conductive material already disposed ontag substrate 116 through an oblation process.

In step 1606, a layer of conductive adhesive is placed on tag substrate116. This step comprises applying an anisotropic adhesive that conductselectricity in a single dimension. One such adhesive is commerciallyavailable “z-axis” adhesive, which is well-known in the relevant arts.Anisotropic adhesives conduct electricity in a single direction.Therefore, they advantageously enable electrical connections to beestablished between connecting pads 204 and related electronics 106without shorting connecting pads 204 together.

In step 1608, die(s) 104 are transferred onto tag substrate 116 in a“pads down” manner. The anisotropic adhesive layer placed on tagsubstrate 116 in step 1606 provides an electrical connection betweeneach connecting pad 204 and corresponding elements of relatedelectronics 106. Step 1608 comprises the steps of placing die(s) 104 incontact with tag substrate 116 and removing die(s) 104 from secondarytransfer surface 1702.

Placing die(s) 104 in contact with tag substrate 116 can include thestep of reducing the physical separation between secondary transfersurface 1702 and tag substrate 116 until die 104 contacts tag substrate116. This can be performed through the use of rollers, piston-typepunching techniques, and/or air jets. FIG. 19 is a view of a “pads down”oriented die 104 in contact with secondary transfer surface 1702 and tagsubstrate 116. As shown in FIG. 19, a punching member 1902 can be usedto punch secondary transfer surface 1702 at a location opposite of die104, to transfer die 104 from secondary transfer surface 1702 to tagsubstrate 116. As describe above, other transfer mechanisms and/orprocesses may be alternatively used.

Removal of die(s) 104 from secondary transfer surface 1702 can includethe steps of providing a stronger adhesive on tag substrate 116 than onsecondary transfer surface 1702, and increasing the physical separationbetween secondary transfer surface 1702 and tag substrate 116.Alternatively, removal of dies 104 from secondary transfer surface 1702can include the steps of providing a release adhesive on secondarytransfer surface 1702 that loses its adhesive properties upon a releaseaction, such as exposure to thermal energy, radiation, or ultravioletlight, and creating a release action at a time when removal is desired.FIG. 20 is a view of a “pads down” oriented die 104 attached to tagsubstrate 116.

2.1.2 Parallel Die Punch onto a Support Surface

According to a parallel die punch process of the present invention, asecond surface, such as a punch tape, is aligned over separated diesattached to a first surface. The punch tape has multiple die receptorholes, “divots,” or cells formed in a surface. Each receptor cell in thepunch tape is aligned with a corresponding die of the first surface.Multiple mechanical punches are actuated to push the die from the firstsurface into the corresponding receptor cell of the punch tape. In thismanner, any number of dies, including tens and hundreds of dies, can betransferred simultaneously into the punch tape, instead of merelytransferring one die at a time.

FIG. 21 shows a flowchart 2100 providing steps for transferring aplurality of dies from a first surface to a second surface using aparallel punching process, according to embodiments of the presentinvention. Note that steps of flowchart 800 that are optional are shownenclosed in dotted lines. Further structural embodiments will beapparent to persons skilled in the relevant art(s) based on thefollowing discussion.

Flowchart 2100 will be described in relation to FIGS. 22-29, forillustrative purposes. A perspective view of an example punch tape 2200is shown in FIG. 22, according to an embodiment of the presentinvention. FIG. 23 shows a cross-sectional view of punch tape 2200. Asshown in FIG. 22, punch tape 2200 has a plurality of cells 2202 formedin a top surface. In some embodiments, punch tape 2200 may further havea plurality of guide holes 2204 formed in the top surface.

As the example shown in FIG. 23, punch tape 2200 may be formed from apunch tape body 2302 and an adhesive tape 2304. Adhesive tape 2304 isattached to a bottom surface of punch tape body 2302. Punch tape body2302 is typically flexible, and may have a variety of thicknesses,including thicknesses ranging from 5 mils to 11 mils, or otherthicknesses. Punch tape body 2302 may be made from plastic or from otherflexible or non-flexible material. Adhesive tape 2304 may be any type ofadhesive tape or other adhesive material. Alternatively, punch tape 2200may be a conventional chip carrier as are available in the industry,and/or may be a single piece punch tape.

Cells 2202 are open on a top surface of punch tape 2200 and are not openon the bottom surface of punch tape 2200. Plurality of cells 2202 areformed from a plurality of openings through punch tape body 2302, havingone end covered by adhesive tape 2304. The openings may be preformed, ormay be formed in punch tape 2200 by laser etching, or by other process.

When present, guide holes 2204 may penetrate all the way through punchtape 2200 to be open at the bottom and top surfaces of punch tape 2200,or may be open at only one of the two surfaces. Guide holes 2204 may beused to align punch tape 2200 with a surface.

In the discussion that follows, punch tape 2200 is described asreceiving dies from a support surface, and transferring dies to asubstrate. However, in embodiments, for example, punch tape 2200 mayreceive dies from a surface that is a scribed wafer or support surface,or an intermediate surface. Furthermore, punch tape 220 may transferdies to an intermediate or transfer surface, or to a substrate surface.

Flowchart 2100 shown in FIG. 21 begins with step 2102. In step 2102, asupport surface is positioned closely adjacent to a surface of a punchtape, such that each die of a plurality of dies attached to a firstsurface of the support surface is closely adjacent to a correspondingempty cell of a plurality of empty cells in the surface of the punchtape. FIG. 24 illustrates step 2102. For example, as shown in FIG. 24,the support surface of step 2102 may be support surface 404, which ispositioned closely adjacent to punch tape 2200. As shown in FIG. 24, aplurality of dies 104 a are attached to support surface 404, and anotherplurality of dies 104 b are attached to the surface of support surface404. Each die of plurality of dies 104 a is positioned closely adjacentto an empty cell 2202 in punch tape 2200.

FIG. 24 also shows a punching apparatus 2402 positioned adjacent tosupport surface 404, according to an example embodiment of the presentinvention. Punching apparatus 2402 includes a body 2404 and a pluralityof punching members 2406. Punching members 2406 are attached to body2404. In embodiments, punching body 2402 may be any type of applicablepunching device, including a flat surface having punching members 2406extending therefrom, or may be a rolling-pin type device with punchingmembers 2406 extending outward radially therefrom. Punching apparatus2402 may be configured in additional ways.

In step 2104, all dies of the plurality of dies are simultaneouslytransferred into closely adjacent, corresponding empty cells from thesupport surface. For example, as shown in FIG. 25, all dies of pluralityof dies 104A are simultaneously being transferred into the correspondingempty cells 2202 of punch tape 2200 by punching apparatus 2402. As shownin FIG. 25, punching mechanism 2402 has moved upward to push each of theplurality of dies 104A into their corresponding cells 2202 by pushingthrough substrate surface 404. As shown in FIG. 25, substrate surface404 substantially flexes to allow punching members 2406 to pushplurality of dies 104 a upwards without substantial damage to supportsurface 404. Although not shown in FIG. 25, plurality of dies 104 abecome attached in cells 2202 due to the adhesiveness of adhesive tape2304, and remain in cells 2202 after punching members 2406 are removedor retracted.

In optional step 2106, the punch tape is incremented relative to thesupport surface to position each die of another plurality of diesattached to the first surface of the support surface closely adjacent toa corresponding empty cell of another plurality of empty cells in thesurface of the punch tape. For example, as shown in FIG. 26, punch tape2200 has been moved and positioned closely adjacent to plurality of dies104 b such that an empty cell 2202 of punch tape 2200 is closelyadjacent to each die of plurality of dies 104 b.

Note that the process of incrementing punch tape 2200 relative tosupport surface 404 means that any one or more of punch tape 2200,support surface 404, and/or punching mechanism 2402 may be moved inorder to properly position these elements relative to dies 104 onsupport surface 404.

In optional step 2108, all dies of the another plurality of dies aresimultaneously transferred from the support surface into closelyadjacent corresponding empty cells. For example, as shown in FIG. 26,punching mechanism 2402 pushes each die of plurality of dies 104 b intothe adjacent cell 2202. Plurality of dies 104 b become attached in cells2202 due to an adhesiveness of adhesive tape 2304.

In optional step 2110, steps 2106 and 2108 can be repeated untilsubstantially all dies attached to the support surface have beentransferred from the support surface to the punch tape. Note thatoptional steps 2106, 2108, and 2110 apply to embodiments where multipleiterations are required to punch plurality of dies from one surface toanother so that all dies attached to the first surface are transferredto the second surface. In other words, for example, the plurality ofdies that are transferred in a single step may be substantially equal toone out of every N dies of a total number of dies attached to thesupport surface. Thus, in such an embodiment, the support surface may bepositioned closely adjacent to the surface of the punch tape, such thateach die of the one out of every N dies attached to the first surface ofthe support surface is closely adjacent to a corresponding empty cell ofthe plurality of empty cells in the surface of the punch tape. Hence,the plurality of dies are transferred, but not all dies.

In an alternative embodiment, the plurality of dies transferred may beall of the dies attached to the first surface, so that furtheriterations are not required. For example, FIG. 27 shows a plurality ofdies 104 attached to support surface 404, where each die is positionedclosely adjacent to corresponding cell 2202 in punch tape 2200. As shownin FIG. 27, punching mechanism 2402 has a plurality of punching members2406 that correspond to plurality of dies 104. Hence, when punchingmembers 2406 simultaneously punch upward into support surface 404, alldies of plurality of dies 104 are moved into corresponding cells 2202 ofpunch tape 2200, simultaneously.

Note that the punch mechanism die transfer embodiments described hereinare applicable to both pads-up and pads-down die orientations. Hence,plurality of dies 104 may be transferred into corresponding cells 2202with pads facing in or out of the corresponding cells 2202, as desired.Furthermore, punching mechanism embodiments may be alternated withadhesive tape transfer embodiments described above in order to flip theorientation of dies 104. Hence, an adhesive tape may be used to transferdies one or more times followed by a final transfer of the plurality ofdies 104 by the punching mechanism. Hence, the adhesive tape embodimentsmay be used to orient the dies with either pads up or pads down prior tobeing punched into cells 2202.

For instance, in an example step 2106, support surface 404 may beincremented by one column of dies 104 relative to punch tape. Punch tape2200 may be spooled on a roll. Punch tape 2200 is advanced so that emptydie receptor cells 2202 are aligned over a column of dies 104 on supportsurface 404. Dies 104 in the column of support surface 404 are punchedinto the empty die receptor cells 2202 in step 2108. Support surface 404may then be again incremented by one column, and punch tape 2200 isagain advanced, so that the next column of dies 104 of support surface404 may be punched into further empty die receptor cells of punch tape2200. This procedure may be repeated until support surface 404 isexhausted of dies 104.

Example die transfer embodiments using a punching mechanism aredescribed in detail in the following subsection.

2.1.2.1 Direct Transfer from Support Surface to Antenna Substrate

According to an embodiment of the present invention, a punchingmechanism may simultaneously transfer each die of a plurality of diesfrom a first surface directly onto a corresponding antenna substrate. Inembodiments where the first surface is a support surface that attachesseparated dies from a wafer, this process allows for extremely rapidfabrication of a large number of electronic devices, such as RFID tags100.

Steps 2102 and 2104 of flowchart 2100 support the transfer for die froma support surface to a substrate, where instead of using a punch tape asa second surface, an substrate is used as the second surface. FIG. 28illustrates an example using punching mechanism 2402 to transfer aplurality of dies 104 from a support surface 404 to a substratestructure 2802 that includes a plurality of tag substrate portions(i.e., tag substrates 116 a-d).

As shown in FIG. 28, punching mechanism 2402 has a plurality of punchingmembers 2406 that are positioned adjacent to dies 104 on an oppositesurface of support surface 404. In a modified step 2102, support surface404 is positioned closely adjacent to a surface of substrate structure2802, such that each die 104 of the plurality of dies is closelyadjacent to a tag substrate 116. Each tag substrate 116 has contactareas 210 a and 210 b for coupling to contact pads 204 a and 204 b ofeach die 104.

Note that an underfill material layer 2804 can be optionally applied tothe surface of substrate structure 2802. This allows for each die 104 tobe underfilled when attached to substrate structure 2802.

In a modified step 2104, all dies 104 of the plurality of dies aresimultaneously transferred onto the closely adjacent, corresponding tagsubstrate 116 from support surface 404. For example, as shown in FIG.28, punching members 2408 may be moved in the direction of arrow 2408 totransfer dies 104. FIG. 29 shows substrate structure 2802 with each ofdies 104 attached to a corresponding one of tag substrates 116 a-d.Underfill material layer 2804 provides for an underfill material to belocated between each die 104 and tag substrate 116. Example underfillmaterials suitable for underfill material layer 2804 are furtherdescribed in the following section.

In this manner, a plurality of RFID tags 100 may be rapidly created,with fewer process steps. Tag substrates 116 a-d shown in FIG. 29 may besubsequently separated to create a plurality of individual RFID tags100. Note that while FIGS. 28 and 29 show the transfer of dies 104directly to tag substrates 116 in a “pads down” orientation, it will beunderstood to persons skilled in the relevant art(s) from the teachingsherein that this transfer of dies 104 directly to tag substrates 116 mayalso be accomplished in a “pads up” orientation.

2.1.2.2 Underfill Material Embodiments

According to a parallel die punch embodiment of the present invention, asecond surface, such as punch tape 2200, is aligned over separated dies104 attached to a first surface. Each receptor cell 2202 in punch tape2202 has a corresponding die 104 placed therein. Each cell 2202 is thenfilled with an underfill material. Punching mechanism 2402 is actuatedto move the die 104 from punch tape 2202 onto corresponding tagsubstrates 116 of substrate structure 2802. In this manner, any numberof dies, including tens and hundreds of dies, can be transferredsimultaneously from punch tape 2200, instead of merely transferring onedie at a time. Furthermore, by applying the underfill material prior totransferring dies 104 to tag substrates 116, each die can be easilyunderfilled on the respective tag substrate 116 during the transferprocess, providing numerous advantages.

FIG. 30 shows a flowchart 3000 providing steps for assembling RFID tags,according to embodiments of the present invention. Note that steps offlowchart 3000 that are optional are shown enclosed in dotted lines.Flowchart 3000 will be described in relation to FIGS. 31-47, forillustrative purposes. Further structural embodiments will be apparentto persons skilled in the relevant art(s) based on the followingdiscussion.

Flowchart 3000 begins with step 3002. In step 3002, a plurality of diesare transferred from a support surface to a chip carrier that has aplurality of cells accessible on a first surface of the chip carrier sothat each die of the plurality of dies resides in a corresponding cellof the plurality of cells and is recessed in the corresponding cell withrespect to the first surface. For example, the chip carrier is a punchtape, such as punch tape 2200 shown in FIG. 31. As shown in FIG. 31,punch tape 2200 has example empty first and second cells 2202 a and 2202b. FIGS. 32 and 33 show first and second dies 104 a and 104 b beingtransferred into first and second cells 2202 a and 2202 b. First andsecond dies 104 a and 104 b may be transferred into first and secondcells 2202 a and 2202 b by any process described here or otherwiseknown, including by a pick and place process. First and second dies 104a and 104 b may be transferred into first and second cells 2202 a and2202 b one at a time, as shown in FIGS. 32 and 33, or simultaneously.Note that two dies are shown in the current example for illustrativepurposes, and that the present invention is applicable to any number ofdies.

In step 3004, an underfill material is applied into each cell of theplurality of cells. For example, as shown in FIG. 34, an underfillmaterial 3402 is applied into first and second cells 2202 a and 2202 bto substantially cover each of dies 104 a and 104 b, shown as first andsecond underfill material portions 3402 a and 3402 b. Underfill material3004 is used to underfill dies 104 when attached to a substrate, such asa tag substrate 116, for purposes such as environmental and hermeticprotection, among other reasons.

In embodiments, underfill material 3402 may be any underfill materialconventionally known to persons skilled in the relevant art(s).Underfill material 3402 may be electrically conductive, or electricallynon-conductive. For example, underfill material 3402 may beisotropically conductive, i.e., substantially uniformly conductive inall directions. Furthermore, underfill material 3402 may beanisotropically conductive, i.e., conductive in a desired direction. Forexample, underfill material 3402 may be a Z-axis epoxy.

In an embodiment, the amount of underfill material 3402 applied in eachcell 2202 can be controlled, so that an amount required by theparticular application is present. For example, FIG. 34 shows first andsecond underfill material 3402 a and 3402 b have been applied so thatthe underfill material extends out of first and second cells 2202 a and2202 b. In another example, FIG. 35 shows first and second underfillmaterial 3402 a and 3402 b have been applied so that the underfillmaterial is flush or even with the top surface of punch tape 2200. Forexample, in order to cause underfill material 3402 to be flush or evenwith the top surface of punch tape 2200, a “squeegee” process may beused. FIG. 36 shows an example squeegee process being performed. Asqueegee element 3602 is passed along the top surface of punch tape2200, smoothing first underfill material 3402 a in first cell 2202 a,for example. An excess underfill material 3604 is shown being removed.In the example of FIG. 36, underfill material 3402 was applied to cells2202 before squeegee element 3602 was applied. Alternatively, underfillmaterial 3402 may be applied by squeegee element 3602.

In the example of FIGS. 34-36, a height of each die 104 is approximatelyequal to half of a height of the corresponding cell 2202. Underfillmaterial 3604 fills a remaining half of the height of the cell 2202.With such an amount of underfill material 3604 in cell 2202 relative tothe size of die 104, enough underfill material 3604 is present tounderfill die 104 when attached to substrate 116, without having excessunderfill material. However, the present invention is applicable tohigher and lower proportions of underfill material 3604 in cells 2202.

In optional step 3006 of flowchart 3000, the first surface of the chipcarrier is positioned closely adjacent to a surface of a substratestructure having a plurality of tag substrate portions. For example,FIG. 37 shows an example substrate structure 2802. Substrate structure2802 includes a plurality of tag substrate portions (i.e., tagsubstrates 116), also referred to as a web or array of tag substrates.Substrate structure 2802 includes any number of tag substrates 116, andmay be shaped into any size column, row, or array of tag substrates 116.FIG. 38 shows substrate structure 2802 of FIG. 37 after having beenseparated into separate strip-shaped tag substrate structures 2802 a,2802 b, 2802 c, and 2802 d. Substrate structure 2802 may be separatedinto strips by sawing, cutting, by laser, and by other processes. Astrip for substrate structure 2802 can be conveniently used to transferdies 104 from punch tape 2200, which typically is also formed in astrip.

FIG. 39 shows a view of a portion of strip-shaped substrate structure2802 a. Substrate structure 2802 includes first and second tagsubstrates 116 a and 116 b. First tag substrate 116 a includes anantenna 114 a and a guide hole 3902 a. Second tag substrate 116 bincludes an antenna 114 b and a guide hole 3902 b.

Guide holes 3902 may be used to align substrate structure 2802 a withpunch tape 2200. For example, guide holes 3902 may be used with guideholes 2204 shown in FIG. 22 to provide alignment. Guide holes 3902 andguide holes 2204 may be used to mechanically or optically alignsubstrate structure 2802 a with punch tape 2202. For example, mechanicalalignment can include aligning punch tape 2202 using a first wheelhaving spaced pegs that interlock with guide holes 2204, and aligningsubstrate structure 2802 a using a second wheel having spaced pegs thatinterlock with guide holes 3902. The first wheel and second wheel aresynchronized.

FIG. 40 shows the top surface of the punch tape 2200 being positionedclosely adjacent to substrate structure 2802 a, according to step 3006.Tag substrate 116 a is positioned closely adjacent to cell 2202 a.

In optional step 3008, a second surface of the chip carrier is punchedproximate to a location opposite of each cell of the plurality of cellsto move each die out of the corresponding cell such that the underfillmaterial covering each die contacts a corresponding tag substrate of theplurality of tag substrate portions. For example, as shown in FIG. 41, apunching member 4102 punches the bottom surface of punch tape 2200opposite to first cell 2202 a. First die 104 moves out of first cell2202 a towards tag substrate 116 a. Underfill material 3402 a contactstag substrate 116 a. As shown in FIG. 42, punching member 4102 movesfirst die 104 until first die 104 comes into contact with tag substrate116 a.

In optional step 3010, the first surface of each die is attached to thecorresponding tag substrate so that the at least one contact pad of eachdie is electrically coupled to at least one corresponding contact pad ofthe corresponding tag substrate. For example, first die 104 is attachedto tag substrate 116 a such that contact pads 204 a-d are electricallycoupled to contact areas 210 a-d of tag substrate 116 a. First die 104 amay be attached to tag substrate 116 a in a variety of ways. Forexample, step 3010 may include the step where underfill material 3402 iscured to attach each die 104 to the corresponding tag substrate 116. Acurable underfill material 3402 may be flash curable, thermally curable,acoustically curable, electron beam curable, ultraviolet (UV) lightcurable, infrared (IR) light curable, pressure curable, and other typeof curable material. Hence, heat, an acoustic source, an electron beam,UV light, IR light, and/or pressure may be applied as needed to cureunderfill material 3402. A two-party epoxy may be used for a flashcurable underfill material, for example.

In an embodiment, curing of underfill material 3402 causes underfillmaterial 3402 to contract or shrink. By contracting, underfill material3402 can cause a decrease in a distance between each die 104 and thecorresponding tag substrate 116, leading to improved mechanical and/orelectrical coupling of contact pads 204 a-d of each die 104 to thecorresponding contact areas 210 a-d of the corresponding tag substrate116. In such an embodiment, underfill material 3402 has a thermalcoefficient of expansion/contraction that dictates the amount ofcontraction when cured. By selecting the material used for underfillmaterial 3402, this coefficient can be tuned. Hence, the thermalcoefficient of underfill material 3402 can by tuned to match that of tagsubstrate 116, or otherwise. For instance, underfill material 3402 canbe tuned to contract by a particular amount, such as 2 times or 3 timesits mass, for example. Underfill material 3402 can be alternatively betuned to apply a particular force over an area, such as 50 kg/cm², forexample.

For example, the contraction of underfill material 3402 can causecontact pads 204 a-d to come into contact with the corresponding contactareas 210 a-d, creating a sufficient electrical connection for operationof the resulting device. Contact pads 204 a-d and/or contact areas 210a-d may be substantially uniform in their smoothness or flatness so thata large area may come into contact between them. In another example,contact pads 204 a-d and/or contact areas 210 a-d may be non-uniform insmoothness or flatness to enhance connectivity. For instance, contactpads 204 a-d (and/or contact areas 210 a-d) may have one or more bumps,spikes, peaks, etc. Thus, when contact pads 204 a-d come into contactwith contact areas 210 a-d, the one or more bumps, spikes, or peaks canpartially or completely penetrate or pierce contact areas 210 a-d,creating an enhanced electrical and mechanical connection.

In another example, in an embodiment, underfill material 3402 includeselectrically conductive microspheres to provide electrical connectivity.The microspheres may be gold, silver, other metal, or combination/alloyof metals, for example. Hence, when curing the contractable underfillmaterial causes the underfill material to contract, a pressure iscreated between each die and corresponding tag substrate. The increasedpressure causes the microspheres to form a contact between the die andsubstrate, and to deform, to electrically couple contact pads 204 a-d tocontact areas 210 a-d.

After die 104 a is attached to tag substrate 116 a, die 104 b can besimilarly attached to tag substrate 116 b. Alternatively, dies 104 a and104 b can be simultaneously attached to their respective tag substrates.

In the example of FIGS. 32-42, dies 104 are oriented to be mounted ontag substrate 116 in a pads down fashion. FIG. 43-47 shows an examplewhere dies 104 are oriented to be mounted on tag substrate 116 in a padsup fashion. For example, as shown in FIG. 43, first and second dies 104a and 104 b have been inserted into cell 2202 a and 2202 b such thatcontact pads 204 a-d face into the cells.

As shown in FIG. 44, punch tape 2200 is positioned closely adjacent totag substrate 116 a of substrate structure 2802 a. As shown in FIG. 45,punch tape 2200 is punched proximate to a location of cell 2202 a tomove die 104 a out of cell 2202 a into a corresponding cell or cavity4402 in tag substrate 116 a such that underfill material 3402 asubstantially fills a gap between an outer edge of die 104 a and cavity4402. As shown in FIG. 45, a surface of die 104 a and a surface ofunderfill material 3402 a is substantially flush or even with thesurface of tag substrate 116 a.

FIG. 46 shows a single die 104 attached in a cavity of tag substrate116. As shown in FIG. 46, in the current example, contact pads 204 a and204 b of die 104 are not electrically coupled to signals of tagsubstrate 116. FIG. 47 shows contact pads 204 a and 204 b of die 104having been electrically coupled to contact areas 210 a and 210 b of tagsubstrate 116 by first and second electrical conductors 4702 a and 4702b. For example, electrical conductors 4702 can be printed, applied by avapor deposition process, soldered, and otherwise formed between contactpads 204 of each die 104 and contact areas 210 on the surface of thecorresponding tag substrate 116.

2.1.3 Multi-Barrel Die Transfer

According to an embodiment of the present invention, a plurality of dies104 may be transferred from a first surface to a second surface using amulti-barrel die transfer apparatus. FIG. 48A shows an examplemulti-barrel die transfer apparatus 4802, according to an embodiment ofthe present invention. Multi-barrel die transfer apparatus 4802 includesa body 4804, and a plurality of barrels 4806. Body 4804 couples barrels4806 to a gas supply and vacuum source 4810. For example, a gas such asair, nitrogen, or other gas may be supplied by vacuum source 4810. Inembodiments, any number of one or more barrels 4806 may be present, buttypically multiple barrels 4806 are present to increase the transferrate of dies 104 by a factor of the number of barrels 4806 present. Forexample, tens or hundreds of barrels may be present.

As shown in FIG. 48A, multi-barrel transfer apparatus 4802 having aplurality of barrels 4806 is positioned over separated dies 104 attachedto a first surface. The first surface is shown as support surface 404 inthe example of FIG. 48A. Each barrel 4806 is positioned so that arespective end 4808 of the barrel 4806 is over a respective die 104 onsupport surface 404. Multi-barrel transfer apparatus 4802 receives thedies 104, storing them in stacks of dies 104 in the plurality of barrels4806. As shown in FIG. 48B, multi-barrel transfer apparatus 4802 is thenpositioned over a second surface. The second surface is shown astransfer surface 1202 in the example of FIG. 48B. Multi-barrel transferapparatus 4802 deposits the dies 104 stored in the barrels 4806 on thesecond surface.

FIG. 49 shows a flowchart 4900 providing example steps for transferringdies, according to an embodiment of the present invention. Forillustrative purposes, steps of flowchart 4900 may be further describedin regards to multi-barrel transfer apparatus 4802, as shown in FIGS.49-52. However, other structural embodiments will be apparent to personsskilled in the relevant art(s) based on the following discussion. Thesesteps are described in detail below.

Flowchart 4900 begins with step 4902. In step 4902, each hollow barrelof a plurality of hollow barrels is applied in parallel to a respectivedie residing on the first surface. For example, FIG. 50 shows across-sectional view of multi-barrel transfer apparatus 4802 beingapplied to first surface 802. The plurality of hollow barrels arebarrels 4806. Barrels 4806 are hollow so that at least a single die 104may pass into barrel 4806 at a time, and be stored therein. As shown inFIG. 48A, each barrel 4806 is applied in parallel with the other barrels4806 to a respective die 104 on the first surface.

In step 4904, the respective die is caused to move into each hollowbarrel in parallel. For example, as shown in FIG. 50, each hollow barrel4806 has a respective die 104 that has moved into the respective hollowbarrel 4806.

In step 4906, steps 4902 and 4904 are repeated to create a stack of diesin each hollow barrel. Hence, for example, multi-barrel transferapparatus 4802 may be moved as many times as needed to position barrels4806 over respective dies so that barrels 4806 may collect therespective dies 104. For example, as shown in FIG. 50, enough dies 104have moved into each barrel 4806 to create a stack 5002 of dies 104 ineach barrel 4806. Stack 5002 as shown in FIG. 50 includes two dies 104,but in embodiments may include any number of dies 104, including tens,hundreds, thousands, and even more dies.

In step 4908, dies from each hollow barrel are deposited in parallelonto the second surface until the stack of dies in each hollow barrel issubstantially depleted. For example, FIGS. 51 and 52 showcross-sectional views of multi-barrel transfer apparatus 4802 beingapplied to various second surfaces 804. As shown in FIGS. 51 and 52,barrels 4806 of multi-barrel transfer apparatus 4802 are depositing dies104 in parallel onto second surface 804. Barrels 4806 deposit dies 104until they are substantially depleted of dies 104. In other words,barrels 4806 can deposit varying amounts of dies 104 onto second surface804, depending on the number of dies required by second surface 804,and/or until one or more barrels 4806 are near or completely depleted ofdies 104.

Second surface 804 may have an adhesiveness that allows for dies 104 tostick thereto. For example, second surface 804 may be an adhesive tape,or may have an adhesive material, such as a wax substance appliedthereto to provide the adhesiveness. As shown in FIG. 51, second surface804 has cells 5102 formed therein, in which dies 104 are deposited frombarrels 4806. Alternatively, as shown in FIG. 52, second surface 804 mayhave a substantially planar surface onto which dies 104 are deposited.Furthermore, as shown in FIGS. 51 and 52, dies may be deposited in apads down or pads up orientation. Barrels 4806 may be reversed end forend after collecting dies 104 in order to change the orientation of dies104 before being deposited on second surface 804. For example, ends 4808and 5004 shown in FIG. 50 may be reversed after collecting dies 104.Alternatively, barrels 4806 can be left un-reversed.

In an embodiment, a vacuum may be used in steps 4904 and 4908 to movedies in and out of barrels 4806. For example, a vacuum source 4810 isshown attached to multi-barrel transfer apparatus 4804 in FIGS. 48A,48B, and 50-51. Vacuum source 4810 may be applied to multi-barreltransfer apparatus 4804 to cause a vacuum or suction in one or morebarrels 4806 to move respective dies 104 into the barrel(s) 4806. Thevacuum or suction may be continuous or applied in controlled bursts.Vacuum source 4810 may also be applied or varied to move dies 104 out ofbarrels 4806 onto second surface 804. For example, vacuum source 4810may apply bursts of positive pressure to move individual dies 104 out ofbarrels 4806.

Barrels 4806 may be configured to allow for proper application of vacuumsource 4810. FIG. 53 shows a cross-sectional top view of an examplebarrel 4806 with die 104 inside, according to an embodiment of thepresent invention. Barrel 4806 may be rectangular as shown in FIG. 53,or may be round, or other shapes. Barrel 4806 may have a smooth interiorsurface 5302 in an embodiment of the present invention. Alternatively,as shown in FIG. 53, interior surface 5302 may have a channel 5304formed in one or more corners to allow gas to pass around dies 104.Channels 5304 may be used to control the vacuum or pressure in barrels4806.

Barrels 4806 may be made from a metal, plastic, or other applicablematerial. For example, barrels 4806 may be barrels, tubes, or needlessimilar to hypodermic needles. Barrels 4806 are configured tocollectively hold any number of dies 104. In an embodiment, the numberand length of each barrel 4806 will be configured to have a cumulativedie 104 holding capacity of at least one wafer worth of dies 104. Forexample, the cumulative holding capacity may be on the order of 50,000to 100,000 of dies 104.

The filled multi-barrel die collet can be moved, robotically orotherwise, to a die dispensing station for tag assembly. An emptymulti-barrel die collet can then be positioned adjacent to a new waferof separated die on a support surface to repeat the process.

Note that other mechanisms and/or processes may alternatively be used instep 4904 to cause dies to move into each hollow barrel, and in step4908 to deposit dies from each hollow barrel. For example, mechanicalstructures and forces, chemical processes and forces, electrostaticforces, adhesive materials, a gas pressure system, and furthermechanisms and processes may be used, as would be understood by personsskilled in the relevant art(s) from the teachings herein.

2.1.4 Die Transfer Using a Die Frame

According to an embodiment of the present invention, a plurality of dies104 may be transferred to a target surface using a “die frame” or “wafertape.” The die frame or wafer tape is formed directly from a wafer tohold the dies of the wafer such that they may be easily transferred tothe target surface. Dies may be transferred from the die frame/wafertape to an intermediate surface, or directly to a final surface, such asa substrate. Thus, the die frame or wafer tape of the present inventionallows for fewer required manufacturing steps when transferring dies toa substrate compared to conventional transfer processes. For example, ina typical conventional process, dies are individually transferred fromthe wafer to an intermediate transfer surface by a pick-and-placemachine. The dies are then transferred from the intermediate surface tothe final destination surface. This two step process allows for the diesto be flipped. According to the present invention, dies can be directlytransferred from the die frame/wafer tape to a substrate, withouttransfer to an intermediate surface. Furthermore, the dies can beflipped or not flipped by the transfer, as needed.

Note that the die frame/wafer tape of the present invention is referredto below as a die frame, for ease of description. The die frame may beformed according to processes of the present invention, some examples ofwhich are described below for purposes of illustration, and notlimitation. FIGS. 57A and 57B show flowcharts for making a die frame,according to example embodiments of the present invention. Furtherembodiments for the die frame of the present invention, and for makingthe die frame of the present invention, will be apparent to personsskilled in the relevant arts based on the following discussion.Furthermore, FIGS. 66 and 68A-B show example flowcharts for transferringdies using a die frame, according to example embodiments of the presentinvention. Further embodiments for transferring dies using the die frameof the present invention will be apparent to persons skilled in therelevant arts based on the discussion herein.

FIG. 57A shows a flowchart 5700 providing example steps for making a dieframe, according to an embodiment of the present invention. Flowchart5700 will be described below in relation to FIGS. 58-63, forillustrative purposes. Flowchart 5700 begins with step 5702. In step5702, a ring shaped groove is formed in a first surface of a waferaround a plurality of dies formed in the first surface of the wafer. Forexample, FIG. 58 shows an example wafer 5800. As shown in FIG. 58, aring shaped groove 5802 has been formed in a surface of wafer 5800closely adjacent to an outer edge of wafer 5800. For example, the depthof ring shaped groove 5802 may be approximately equal to the thicknessof an integrated circuit die, such as die 104, that is formed in thesurface of wafer 5800 (not shown in FIG. 58). In the example of FIG. 58,ring shaped groove 5802 is substantially round or elliptical, and iscontinuous. In alternative embodiments, ring shaped groove 5802 may beformed in other shapes, including square or other polygon. Furthermore,ring shaped groove 5802 does not necessarily have to be continuous, asshown in the example of FIG. 58, but may be instead be non-continuous,and for example, may include two or more separate portions formed in thesurface of wafer 5800.

In step 5704, the first surface of the wafer is scribed to form a gridof grooves in the first surface of the wafer that separates theplurality of dies. For example, FIG. 59 shows wafer 5800 after havingbeen scribed. The scribing of wafer 5800 has created a grid 5902 in thesurface of wafer 5800. Grid 5902 is formed from a plurality ofhorizontal and vertical grooves 5904 formed in the surface of wafer5800. For example, a first groove 5904A, a second groove 5904B, a thirdgroove 5904C, and a fourth groove 5904D of grid 5902 are indicated inFIG. 59. Within grid 5902 resides a plurality of areas of the surface ofwafer 5800 in which dies 104 may reside. For example, FIG. 59 shows anarea for a first die 104 a and an area for a second die 104 b thatreside within grid 5902. Note that features of dies 104 are not shown inFIG. 58 and FIG. 59.

FIG. 60 shows a cross sectional view of a portion of wafer 5800. Asshown in FIG. 60, ring shaped groove 5802 and grooves 5904 a and 5904 bhave a thickness or depth of depth 6002. For example, depth 6002 may be100 micrometers, or other thickness. Depth 6002 is typically equal to orgreater than a thickness of a die of wafer 5800. As shown in FIG. 60,wafer 6004 has a thickness 6004. Thickness 6004 can be any thickness ofa conventional or special purpose wafer, which may be 600 to 700micrometers or other thickness, for example.

In step 5706, a solidifiable material is applied to the first surface ofthe wafer to substantially fill the ring shaped groove and the groovesof the grid. FIG. 61 shows, for example, a solidifiable material 6102that has been applied to the surface of wafer 5800 to substantially fillring shaped groove 5802 and grooves 5904 of grid 5902. Solidifiablematerial 6102 substantially fills ring shaped groove 6102 and grooves5904. For example, solidifiable material 6102 may fill the grooves to alevel below the surface of wafer 5800, to the same level as the surfaceof wafer 5800 (as shown in FIG. 62), or even to slightly protrude abovethe surface of wafer 5800. Solidifiable material 6102 may be a polymer,epoxy, resin, urethane, glass, or other material, for example.

A variety of processes may be used to cause solidifiable material 6102to fill grooves 5802 and 5904 when applied to wafer 5800, withoutleaving a substantial excess amount of solidifiable material 6102otherwise on the surface of wafer 5800. For example, a vacuum source maybe applied to the opposite surface of wafer 5800, or to a tape, such asa blue or green tape, to which wafer 5800 is attached, to causesolidifiable material 6102 to be pulled into grooves 5802 and 5904. Inanother embodiment, a gas source may direct a gas towards the surface ofwafer 5800 to which solidifiable material 6102 is being applied, toblow, force, or push solidifiable material 6102 into grooves 5802 and5904. In another embodiment, solidifiable material 6102 is applied tothe surface of wafer 5800 in a spin-coating fashion, such that aspinning motion of wafer 5800 causes solidifiable material 6102 to moveor “wick” into grooves 5802 and 5904. Solidifiable material 6102 may beapplied in additional ways to fill grooves 5802 and 5904, including by“squeegee” application, spraying, vapor deposition, physical deposition,or chemical deposition.

In step 5708, the solidifiable material is caused to harden into a ringshaped hardened material in the ring shaped groove, and into a gridshaped hardened material in the grooves of the grid to form the dieframe. For instance, in the example of FIGS. 61 and 62, solidifiablematerial 6102 is caused to hardened in ring shaped groove 5802, and ingrooves 5904 of grid 5902. In an embodiment, the hardened material isformed by causing solidifiable material 6102 to hardened by a curingprocess. Hence, solidifiable material 6102 may be any curable material,such as a curable polymer, epoxy, resin, urethane, glass, or othermaterial, for example. Solidifiable material 6102 may be a material thatis caused to harden in a variety of ways, including by heat, by allowinga sufficient amount of time for solidifiable material 6102 to hardenedon its own, by applying light, or by other ways described elsewhereherein or otherwise known.

In step 5710, the wafer is thinned such that the grid shaped hardenedmaterial removably holds the plurality of dies. For example, FIG. 63shows a die frame 6300 formed according to the present invention. Dieframe 6300 includes a hardened material 6304 resulting from thehardening of solidifiable material 6102 in ring shaped groove 5802 andgrooves 5904 of grid 5902, as described above. Die frame 6300 furtherresults from the thinning of wafer 5800. As shown in FIG. 63, wafer 5800has been thinned to form die frame 6300 of a thickness of approximatelydepth 6002. In embodiments, die frame 6300 can be formed or thinned tohave a thickness of approximately equal to depth 6002, or a lesserthickness. Thus, because die frame 6300 has a thickness approximatelyequal to or less than depth 6002, die frame 6300 removably holds dies104 in corresponding openings 6302. In other words, dies 104 can beeasily removed from openings 6302. For example, as shown in FIG. 63, dieframe 6300 removably holds die 104A in opening 6302A, and removablyholds die 104B in an opening 6302B. Die frame 6300 provides a supportstructure in the shape of ring shaped groove 5802 and grid 5904 that iscapable of removably holding dies 104 in openings 6302. Dies 104 may beremoved from die frame 6300 by pushing, poking, or otherwise forcingthem out of openings 6302 from either surface of die frame 6300 ontoanother surface. Depending on which surface of die frame 6300 that dies104 are forced from will determine whether dies 104 are transferred to asurface in either a pads up or a pads down orientation.

Note that wafer 5800 may be thinned in step 5710 according to anyconventional or otherwise known means. Furthermore, note thatsolidifiable material 6102 is selected so that it does not substantiallyadhere to die 104, so that dies 104 may be easily removed from die frame6300 and are thus removably held therein.

FIG. 57B shows a flowchart 5720 providing example steps for making a dieframe, according to another embodiment of the present invention.Flowchart 5720 will be described below in relation to FIGS. 64A-64C,65A, and 65B, for illustrative purposes. Flowchart 5720 begins with step5722. In step 5722, a wafer attached to an adhesive surface is scribedsuch that a resulting plurality of dies are separated by a grid ofgrooves that extend through the wafer to the adhesive surface. Forexample, FIG. 64A shows a scribed wafer 6402 attached to an adhesivesurface 6404. Adhesive surface 6404 is held in a wafer frame 6406. Waferframe 6406 may also be referred to as a wafer carrier or tape ring. Forexample, adhesive surface 6404 may be a green tape, blue tape, or otheradhesive surface type. Wafer frame 6406 holds and supports adhesivesurface 6404 in a taut fashion so that scribed wafer 6402 may beaccessed. Because wafer 6402 has been scribed, wafer 6402 has a grid5902 of grooves 5904 (not shown in FIG. 64A) that separates the dies 104of wafer 6402. Wafer 6402 is scribed so that grooves 5904 extend throughwafer 6402 to adhesive surface 6404. Hence, dies 104 of wafer 6402 areindividually attached to adhesive surface 6404. FIG. 64B shows across-sectional view of an example scribed wafer 6402 having three dies104 separated by grooves 5904. Note that wafer 6402 is shown with threedies 104 for purposes of illustration, and not of limitation. FIG. 64Cshows a perspective view of a portion of an example scribed wafer 6402attached to adhesive surface 6404, having a plurality of dies 104separated by grooves 5904 of grid 5902.

In step 5724, a solidifiable material is applied to the scribed wafer tosubstantially fill the grooves of the grid. For example, as shown inFIG. 65A, solidifiable material 6102 is applied to scribed wafer 6402 topartially or completely fill grooves 5904 between dies 104. As shown inFIG. 65A, solidifiable material 6102 a fills grooves 5904 between dies104. In an embodiment, solidifiable material 6102 may be applied suchthat solidifiable material 6102 b is present to fill a space 6500 onadhesive surface 6404 between an outer edge 6502 of wafer 6402 and aninner edge 6504 of wafer frame 6406. Note that in an embodiment,solidifiable material 6102 may even extend partially within wafer frame6406, as shown in FIG. 65A, although this is not required. Solidifiablematerial 6102 may be applied in any manner described elsewhere herein,such as is described above in relation to FIGS. 61 and 62, or otherwiseknown.

In step 5726, the solidifiable material is caused to harden into a gridshaped hardened material in the grooves of the grid. For example,solidifiable material 6102 a and 6102 b shown in FIG. 65A is caused toharden into a grid shaped hardened material, such as is described abovefor hardened material 6304 in relation to FIG. 63.

In step 5728, the adhesive surface is removed so that the grid shapedhardened material removably holds the plurality of dies. For example,FIG. 65B shows a die frame 6300 that results from the removal ofadhesive surface 6404. Hardened material 6304 a is present between dies104, and hardened material 6304 b is present outside of dies 104.Hardened material 6304 removably holds dies 104 in the shape of a gridin die frame 6300, as described above. Note that adhesive surface 6404may be removed or detached by peeling, chemically dissolving, orotherwise removing it from die frame 6300.

Note that die frame 6300 may be formed in a pads up or pads downfashion. For example, flowchart 5720 may include steps similar to steps702, 704, and 706 shown in flowchart 700 of FIG. 7, for flipping theorientation of dies 104 prior to performance of step 5722. Thus, thepads of dies 104 may be facing toward or away from adhesive surface6404, depending on which orientation is selected.

The structure of die frame 6300 has numerous advantages. For example,the portion of die frame 6300 formed in a ring shape in ring shapedgroove 5802 allows for a holding mechanism, such as a clamp or jig, toreliably hold die frame 6300 when being used for transferring dies, forexample. The portion of die frame 6300 formed in a grid shape in grid5904 allows for the holding of dies 104, with relative ease in removalof dies 104, as described below. The structure of die frame 6300 hasfurther benefits. Note that in some embodiments, the ring shaped portionof die frame 6300 may not be necessary, and is not present.

Preferably, excess solidifiable material 6102 is not left on the surfaceof wafer 5800. In embodiments, flowchart 5700 may include an additionalstep that is performed prior to step 5704, where a layer of protectivematerial is applied onto the surface of the wafer. The protectivematerial, for example, may be a photo-resist material, or otherprotective material, which may be spin coated or otherwise applied tothe surface of the wafer. Thus, in an embodiment, flowchart 5700 mayalso include the step where the protective material is removed from thesurface of the wafer. For example, removing the protective material fromthe wafer can cause the removal of excess solidifiable material 6102 inits hardened state or in its unhardened state (i.e., prior to or afterstep 5708). For example, wafer 5800 may be immersed in a solvent, or mayhave a solvent applied thereto to dissolve the protective material fromthe surface of wafer 5800. The protective material may be removed from5800 by other ways that are known to persons skilled in the relevantarts.

Die frame 6300 may be used to transfer dies 104 to a subsequentdestination or transfer surface. The subsequent surface can be anintermediate surface, such as a blue or green tape, or intermediatesurfaces otherwise known or described elsewhere herein, or may be usedto transfer dies 104 to a final destination surface, such as asubstrate. Furthermore, die frame 6300 allows for precise transfer ofdies. For example, because the location of dies removably held in dieframe 6300 is accurately known, precise registration of dies is present.Thus, expensive optical and/or other type registration systems may notbe required to locate and accurately place dies.

FIG. 66 shows a flowchart 6600 providing steps for transferring aplurality of dies to a surface using a die frame, according toembodiments of the present invention. Note that steps of flowchart 6600that are optional are shown enclosed in dotted lines. Flowchart 6600will be described in relation to FIG. 67, for illustrative purposes.Further structural embodiments will be apparent to persons skilled inthe relevant arts based on the following discussion.

Flowchart 6600 begins with step 6602. In step 6602, a die frame ispositioned closely to a surface of a substrate tape that includes aplurality of substrates such that a die of a plurality of dies removablyheld in the die frame is closely adjacent to a corresponding substrateof the plurality of substrates of the substrate tape. For example, FIG.67 shows a system 6700 for transferring dies to a surface using dieframe 6300. System 6700 includes die frame 6300, punching member 2406, adie frame jig 6702, a first reel 6706, a second reel 6708, and asubstrate tape 6710. As shown in FIG. 67, substrate tape 6710 includes aplurality of substrates 6712 a-c. Substrate tape 6710 may include anynumber of substrates 6712. As shown in FIG. 67, die frame 6300 ispositioned closely adjacent to a surface of substrate tape 6710. Dieframe 6300 is positioned closely adjacent to substrate tape 6710 suchthat a die 104 may be punched from die frame 6300 to a substrate 6712 ofsubstrate tape 6710, as is described below.

In step 6604, the die is transferred onto the closely adjacentcorresponding substrate from the die frame. As shown in FIG. 67, die 104has been transferred from die frame 6300 to a surface of substrate 6712b of substrate tape 6710. For example, as shown in FIG. 67, die 104 maybe punched from die frame 6300, which removably holds die 104, ontosubstrate 6712 a. For example, a punching mechanism 2406 may be used topunch die 104 from die frame 6300 onto substrate 6712 a. In furtherembodiments, other mechanisms may be used to transfer die 104 from dieframe 6300 to a substrate 6712.

Multiple dies may be transferred from die frame 6300 to substrate tape6710 in this manner. In step 6606, the substrate tape is incremented.For instance, as shown in the example of FIG. 67, substrate tape 6710may include a plurality of substrates 6712 that are serially arranged.Substrate tape 6710 may be incremented according to a reel-to-reelsystem, such as shown in FIG. 67. In FIG. 67, a first reel 6706 maysupply substrate tape 6710 to a second reel 6708, which receivessubstrate tape 6710. By turning first and second reels 6706 and 6708,substrate tape 6710 may be incremented to move a next substrate 6712into position to receive a die 104 from die frame 6300. Other mechanismsmay be used to increment substrate tape 6710. Furthermore, inalternative embodiments, substrate tape may include an N×M array ofsubstrates 6712, where N>1 and M>1, instead of having substrates 6712serially aligned.

In step 6608, the die frame is positioned closely adjacent to thesurface of the substrate tape such that another die of a plurality ofdies removably held in the die frame is closely adjacent to a nextcorresponding substrate of the plurality of substrates of the substratetape. For example, shown in FIG. 67, die frame 6300 is held in a dieframe jig 6702. Die frame jig 6702 may be moved laterally relative tosubstrate tape 6710 to position the next die 104 over the next substrate6712, such as substrate 6712 a or 6712 b. Because the size of a die 104is well known, the die frame jig 6702 may be repositioned by the widthor length of a die 104, instead being repositioned by an optical and/orother registration system type which has to determine the location of adie. For example, in an embodiment, for a 500 x 500 micron sized die,die frame jig 6702 may be moved by 500 microns (possibly plus the widthof a groove 5904) to place the next die 104 into position for transfer.Note that the present invention is applicable to any size die.

In step 6610, another die is transferred onto the closely adjacent nextcorresponding substrate from the die frame. Thus, in this manner aplurality of dies 104 may be transferred from die frame 6300 on tocorresponding substrates 6712 of substrate tape 6710. In this manner,for example, a large number of tag substrate/die combinations may becreated in a relatively rapid fashion, in fewer steps than withconventional processes.

Note that multiple die frames 6300 may be placed in a stack, from whichdies 104 may be transferred to a destination surface. The dies 104 maybe transferred from the stack of die frames 6300 to the destinationsurface using a punching mechanism, a vacuum/gas source, and any othermechanism described elsewhere herein or otherwise known. For example,FIG. 68A shows a flowchart 6800 providing steps for transferring aplurality of dies to a surface using a stack of die frames, according toanother embodiment of the present invention. Note that steps offlowchart 6800 that are optional are shown enclosed in dotted lines.Further structural embodiments will be apparent to persons skilled inthe relevant arts based on the following discussion.

Flowchart 6800 will be described in relation to FIG. 69, forillustrative purposes. Flowchart 6800 begins with step 6802. In step6802, a stack of die frames is formed, each die frame including a gridhaving a plurality of rectangular openings, wherein each opening of theplurality of rectangular openings removably holds a die, whereincorresponding rectangular openings of the die frames in the stack arealigned in a column to form a plurality of columns of openings. Forexample, FIG. 69 shows a stack of die frames 6902. Stack 6902 includes aplurality of die frames 6300. For illustrative purposes, stack 6902 isshown including six die frames 6300 a-f, but may include any number oftwo or more die frames 6300. As described above, each die frame 6300includes hardened material 6304 shaped in the form of grid 5902. Aplurality of openings 6302 are present in each die frame 6300, eachremovably holding a die 104. Die frames 6300 are aligned so thatcorresponding openings 6302 form columns in the stack 6902 (not shown inFIG. 69).

In step 6804, a die removably held in an opening is transferred from atleast one column of the plurality of columns to the destination surface.In other words, one or more dies 104 are transferred from stack 6902from one or more columns to the destination surface. Dies 104 may betransferred in numerous ways from stack 6902. For example, as shown inFIG. 69, one or more punching members 2406 may be applied tocorresponding columns of openings 6302 in stack 6902. A punching member2406 pushes through stack 6902 to move dies 104 from the respectivecolumn of openings 6302 in stack 6902 to the destination surface. Apunching member 2406 may be stepped to push out a single die 104 at atime. Any number of punching members 2406 may operate in parallel, suchas punching members 2406 a-c as shown in the example of FIG. 69, toincrease the rate of die transfer.

Other processes for transferring dies 104 from stack 6902 may be used,including the use of a gas or vacuum source to apply gas pressure,electrostatic force, pick and place devices, and processes describedelsewhere herein, or otherwise known. Another example such process isdescribed in detail below with respect to FIG. 68B.

Note that the destination surface may be a substrate tape or structure,as shown in FIG. 69. Alternatively, the destination surface may be apunch tape or chip carrier, such as shown in FIG. 22, any intermediatesurface, such as a green tape or blue tape, or any other surface.Furthermore, dies 104 may be transferred to the destination surface in apads up or down configuration, depending on the orientation of stack6902. Stack 6902 may be inserted into a die deposition apparatus thatholds and aligns the respective die frames 6300 in a stack, and allowsdies to be transferred therefrom.

Further detail for an example embodiment of flowchart 6800 is shown inFIG. 68B. FIG. 68B will be described in relation to FIG. 70, forillustrative purposes. FIG. 70 shows a system 7000 for transferring diesfrom a die frame 6300 using a multi-barrel die transfer apparatus 4802,according to an embodiment of the present invention. As shown in FIG.70, multi-barrel die transfer apparatus 4802 includes a plurality ofbarrels 4806 a-c. Furthermore, system 7000 includes a stack 6902 of dieframes 6300 which includes first, second, third, and fourth die frames6300 a-d. Stack 6902 may include any number of die frames 6300.

In step 6802, a stack of die frames is formed, each die frame includinga grid having a plurality of rectangular openings, wherein each openingof the plurality of rectangular openings removably holds a die, whereincorresponding openings of the die frames in the stack are aligned in acolumn. As shown in FIG. 70, for example, the die frames 6300 a-d of dieframe stack 6902 are aligned such that a plurality of columns 7002 areformed. Each column 7002 includes a die removably held in an opening ineach of die frames 6300 a-d.

In step 6812, each hollow barrel of a plurality of hollow barrels isapplied to a respective column of openings of the stack of die frames.For example, as shown in FIG. 70, a first column 7002 a has first barrel4806 a applied thereto, a second column 7002 b has second barrel 4806 bapplied thereto, and a third column 7002 c has a third barrel 4806 capplied thereto.

In step 6814, dies removably held in the openings of the respectivecolumn of openings are caused to move into each hollow barrel inparallel. As shown in FIG. 70, dies 104 that were removably held in dieframes 6300 a-6000 d are caused to move into barrels 4806. Dies 104 maybe caused to move into the hollow barrels 4806 by vacuum, by gaspressure, by mechanical means, or other means described elsewhere hereinor otherwise known.

In step 6816, steps 6812 and 6814 are repeated until each hollow barrelcontains a stack of dies of a predetermined number. For example, steps6812 and 6814 may be repeated until one or more of barrels 4806 a-cbecome full, until stack 6902 is depleted of dies, or when an arbitrarynumber of dies 104 have been moved from stack 6902.

In step 6818, a die from each hollow barrel is deposited onto thesurface until the stack of dies contained by each hollow barrel issubstantially depleted. Thus, dies 104 from hollow barrels 4806 may bedeposited onto the destination or target surface, until the dies 104 inhollow barrels 4806 are depleted, or until the surface is full of dies104, or until an arbitrary number of dies 104 have been transferred. Asdescribed above, dies 104 may be deposited from hollow barrels 4806 bymechanical means, by vacuum, by gas pressure or by other means describedelsewhere herein or otherwise known.

Hence, die frame 6300 may be used in a variety of ways to transfer diesto a target surface. Furthermore, die frame 6300 may be combined withany of the other die transfer mechanisms and processes describedelsewhere herein to provide for enhanced die transfer mechanisms andprocesses. Further example die frame embodiments are described in thefollowing subsections, for illustrative purposes.

2.1.4.1 Die Frame Formed in a Tape Structure

In an embodiment, a die frame may be formed in a flexible, planar tapestructure, similar to a “blue tape” or “green tape” used to attachwafers/dies. The tape structure is fabricated to include a hardenablematerial or substance. A wafer is attached to the tape structure, and isseparated into a plurality of dies. The tape structure is processed tocause a hardened grid structure to form in the tape structure, whichremovably holds the plurality of dies. FIG. 71 shows a flowchart 7100providing steps for making such a die frame or die support frame,according to an example embodiment of the present invention. Flowchart7100 is described below in relation to FIGS. 72, 73A, 73B, and 74 forillustrative purposes.

Flowchart 7100 begins with step 7102. In step 7102, a wafer thatcomprises a plurality of dies is attached to a surface of a tapestructure. For example, as described above, FIG. 4B shows a wafer 400attached to an example support surface 404. As shown in FIG. 4A, wafer400 includes a plurality of dies 104. In the present embodiment, wafer400 is attached in a similar fashion to a tape structure. The surface ofthe tape structure and/or wafer 400 may have an adhesive materialapplied thereon to adhere wafer 400 to the tape structure. The tapestructure is described in further detail below.

In step 7104, a grid of grooves is formed in the wafer to separate theplurality of dies on the surface of the tape structure. For example,FIG. 72 shows wafer 400 attached to a surface 7202 of a tape structure7200, according to an example embodiment of the present invention. Wafer400 is separated into a plurality of dies 104 on surface 7202. Wafer 400may be separated into a plurality of dies 104 on tape structure 7200according to any conventional wafer separation technique, includingscribing or separating wafer 400 by sawing, laser, mechanical orchemical etching, and other techniques. The separation of wafer 400creates grid 5902 of grooves 5904 in wafer 400.

Tape structure 7200 is a flexible structure that comprises a hardeningor solidifiable material that can be caused to harden by varioustechniques. For example, tape structure 7200 may include a material thatcan be caused to harden by the application of light, including byapplication of ultraviolet (UV) or other frequency bands of light.Alternatively, tape structure 7200 may include a material that may becaused to harden by the application of a solid, liquid, or gas, thatreacts with the material of tape structure 7200 to cause portions oftape structure 7200 to harden or solidify.

All or a portion of tape structure 7200 may comprise the material thatcan be caused to harden. For example, FIG. 73A shows a cross-sectionalview of tape structure 7200 as a single layer structure having thesolidifiable or hardenable material throughout. Alternatively, FIG. 73Bshows tape structure 7200 as a multi-layer structure that includes asolidifiable or hardenable material layer 7302. Layer 7302 can befabricated into tape structure 7200, or can be spread, applied, orsprayed onto tape structure 7200. For example, the solidifiable orhardenable material may be a photoresist material or an epoxy applied totape structure 7200. Tape structure 7200 may further include a paper,tape, polymer, or other material layer to provide structural support.

Note that steps 7102 and 7104 may be performed by structure(s) describedherein or otherwise known, and may be performed by the same structure,or different structures. For example, a wafer preparation module mayperform steps 7102 and 7104. An example such wafer preparation module isfurther described in sections 3.0-3.2 below. The wafer preparationmodule may include a wafer application apparatus, for applying a waferto tape structure 7200, and/or may include a wafer singulation apparatusfor separating/singulating the wafer on surface 7202.

In step 7106, a portion of the tape structure that is accessible throughthe grooves of the grid is caused to harden into a grid shapedstructure. For example, FIG. 74 shows an example system 7400 for causingthe portion of tape structure 7200 that is accessible through grooves5904 of grid 5902 to harden into a grid shaped structure. As shown inFIG. 74, a hardening agent source 7402 transmits a hardening agent 7404towards separated wafer 400 and tape structure 7200. Due to the locationof dies 104, hardening agent 7404 reaches tape structure 7200 throughgrooves 5904 and at peripheral areas. Thus, portions of tape structure7200 that are accessible through grooves 5904 and in peripheral areasare caused to harden, shown as hardened groove portions 7410 andhardened peripheral areas 7420, respectively. Portions of tape structure7200 that are not accessible to hardening agent 7404 (due to theapplication of hardening agent 7404 being blocked by dies 104) do notharden. For example, FIG. 74 shows an example portion 7430 of tapestructure 7200 that is not hardened.

Hardening agent source 7402 can include various sources for hardeningagents, depending on the type of hardening or solidifiable material intape structure 7200. For example, hardening agent source 7402 caninclude a light source and respective optics, including a UV lightsource or infrared (IR) light source, for a material that hardens withexposure to light. For example, the hardening material may be aphotoresist material. In such an embodiment, hardening agent 7404 may belight, such as UV, IR, or other frequency band of light.

Alternatively, hardening agent source 7402 can include a gas or liquidsupply for applying or spraying a gas or liquid towards separated wafer400 and tape structure 7200. For example, hardening agent 7404 may be anepoxy of a two-party epoxy, to react with a corresponding epoxyincorporated in tape structure 7200. Other hardening agent sources andhardening agents are applicable to the present invention, including aheat source.

A die frame 7460 is thereby formed. The die frame 7460 formed accordingto flowchart 7100 removably holds the plurality of dies 104. Thus, oneor more dies 104 of the plurality of dies 104 can be moved from the gridshaped structure of die frame 7460 onto a target surface. FIG. 75 showsa die frame 7460 that includes an example grid shaped structure 7500.Die frame 7460 is held by a die frame jig 6702. As shown in FIG. 75, adie 104 is being moved from die frame 7460 to a substrate 6712. In theexample of FIG. 75, die 104 is being moved by a punching member 2406.Die 104 may be moved from die frame 7460 in a variety of ways, includingby punching, by action of a gas, and by other ways otherwise known ordescribed elsewhere herein.

Note that each non-hardened area 7430 may or may not tear from die frame7460 when the respective die 104 is moved from die frame 7460.

Die frame 7460 may be used in a variety of ways to transfer dies 104 toa target surface, including any of the ways for transferring diesdescribed elsewhere herein. Furthermore, die frame 7460 may be combinedwith any of the other die transfer mechanisms and processes describedelsewhere herein to provide for enhanced die transfer mechanisms andprocesses.

2.1.4.2 Die Frame Formed by Releasing Encapsulated Hardenable Material

In an embodiment, a die frame may be formed on a planar tape structure,similar to a “blue tape” or “green tape” used to attach wafers/dies. Thetape structure is fabricated to include an encapsulated, releasablematerial or substance that hardens. A wafer is attached to the tapestructure, and is separated into a plurality of dies. The process ofseparating the wafer into dies breaches the tape structure, whichreleases the encapsulated material. The released material hardens tocreate a hardened grid structure on the tape structure, which removablyholds the plurality of dies. The remainder of the tape structure maythen be optionally removed. FIG. 76 shows a flowchart 7600 providingsteps for making such a die frame or die support frame, according to ananother example embodiment of the present invention. Flowchart 7600 willbe described below in relation to FIGS. 77-82, for illustrativepurposes.

Flowchart 7600 begins with step 7602. In step 7602, a wafer thatcomprises a plurality of dies is attached to a surface of a tapestructure, wherein the tape structure comprises an encapsulatedreleasable hardening or hardenable material. For example, as describedabove, FIG. 4B shows wafer 400 attached to an example support surface404. As shown in FIG. 4A, wafer 400 includes a plurality of dies 104. Inthe present embodiment, wafer 400 is similarly attached to a tapestructure. However, in the current embodiment, the tape structurecomprises an encapsulated hardening or solidifiable material that can bereleased and hardened.

For example, FIG. 77 shows wafer 400 attached to a surface 7706 of atape structure 7702. Surface 7706 and/or wafer 400 may have an adhesivematerial applied thereto to adhere wafer 400 to surface 7706.

Tape structure 7702 may be a single or multi-layer structure. An examplemulti-layer structure for tape structure 7702 is shown in FIG. 77. Asshown in FIG. 77, tape structure 7702 includes a layer 7704. Layer 7704comprises an encapsulated hardening material that can be released andhardened. For example, layer 7704 may include a gas, liquid, or solidthat is released from layer 7704, and hardens, when a proper agent isapplied to layer 7704. The operation and structure of layer 7704 isfurther described below.

Tape structure 7702 is typically flexible, but may also be rigid. Asshown in the example embodiment of FIG. 77, tape structure 7702 caninclude a tape layer 7708 for added structural support, although tapelayer 7708 is not required. Tape layer 7708 may be made from a varietyof materials. For example, tape layer 7708 may be a paper, a polymer, asubstrate material, a glass, a metal or combination of metals/alloy, aplastic, or other suitable substance, or combination thereof.

In step 7604, a grid of grooves in the wafer is formed to separate theplurality of dies on the surface of the tape structure, including thestep of breaching the surface of the tape structure in the grooves tocause the encapsulated hardening material to harden in the grooves intoa grid shaped hardened material in the grooves of the grid. For example,FIG. 78 shows a cross-sectional view of wafer 400 being separated intoseparate dies 104 on surface 7706 of tape structure 7702, according toan example embodiment of the present invention. The separation of wafer400 creates grid 5902 of grooves 5904 (similarly to as shown in FIG.59).

Wafer 400 may be separated into a plurality of dies 104 on tapestructure 7702 according to any conventional wafer separation technique,including scribing or separating wafer 400 by sawing, laser, mechanicalor chemical etching, and other techniques. For example, FIG. 78 shows across-sectional view of wafer 400 being separated into a plurality ofdies 104 using a laser 7810, according to an embodiment of the presentinvention. FIG. 79 shows a perspective view of a portion of wafer 400being separated into a plurality of dies 104 using a saw 7910, accordingto another embodiment of the present invention.

As recited in step 7604, forming the grid of grooves breaches thesurface of the tape structure in the grooves to cause the encapsulatedhardening material to harden in the grooves into a grid shaped hardenedmaterial. For example, as shown in each of FIGS. 78 and 79, surface 7706of tape structure 7702 is breached. An example breach in surface 7706 isindicated as a breach 7820. A sufficient breach 7820 occurs in surface7706 along the length of each of grooves 5904 so that the encapsulatedhardening material substantially fills each groove 5904. Breach 7820 mayhave any width and depth necessary to release a sufficient amount ofencapsulated hardening material. Depending on the particular separationtechnique used to create a breach 7820, the respective breach 7820 maybe an opening, a tear, a rupture, or a scratch in surface 7706.

FIGS. 78 and 79 each show a released hardening material 7802 thatpartially or completely fills a respective groove 5904. Breach 7820releases hardening material 7802 from layer 7704 of tape structure 7702.Hardening material 7802 can be a gas, liquid, solid, or combinationthereof. For example, the material encapsulated in layer 7704 may bereleased as a foam, gel, epoxy, or other liquid. Hardening material 7802may be caused to harden in a variety of ways. For example, in anembodiment, hardening material 7802 hardens when it meets the ambientair, or when it meets a selected gas or combination of gases. In anotherembodiment, hardening material 7802 hardens when it is heated by theparticular wafer separation technique, such as the heat generated bycontact with the beam of laser 7810 or by the action of saw 7910. Inanother embodiment, hardening material 7802 hardens when it contacts ormixes with an epoxy or other material.

In another embodiment, layer 7704 may include micro-encapsulated spheresor beads that contain the hardening material. The spheres or beads areruptured when the particular wafer separation technique breaches layer7704. The hardening material is released from the spheres or beads and,and hardens when heated, when contacting air or other gas, or otherwise.

FIG. 80 shows a perspective view of a portion of a separated wafer 400on tape structure 7702, with hardening material 7802 forming a gridshaped hardened material 8000 around a plurality of dies 104, accordingto an example embodiment of the present invention.

Note that steps 7602 and 7604 may be performed by structure(s) describedherein or otherwise known, and may be performed by the same structure,or different structures. For example, a wafer preparation module mayperform steps 7602 and 7604. An example such wafer preparation module isfurther described in section 3.0-3.2 below. The wafer preparation modulemay include a wafer application apparatus, for applying a wafer to tapestructure 7702, and/or may include a wafer singulation apparatus forseparating/singulating the wafer on surface 7706, and for breachingsurface 7706. The wafer singulation apparatus may include laser 7810and/or saw 7910, for example.

In step 7606, the tape structure is removed so that the grid shapedhardened material removably holds the plurality of dies. FIG. 81 shows adie frame 8100 that has been detached from tape structure 7702,according to an example embodiment of the present invention. Tapestructure 7702 may be peeled, dissolved, etched, or otherwise removed.

Die frame 8100 is thus formed according to flowchart 7600. Die frame8100 may be used in a variety of ways to transfer dies to a targetsurface, including any of the ways for transferring dies describedelsewhere herein. Furthermore, die frame 8100 may be combined with anyof the other die transfer mechanisms and processes described elsewhereherein to provide for enhanced die transfer mechanisms and processes.

2.2 Post Processing

As described herein with reference to FIG. 3, in step 310, postprocessing is performed to complete assembly of RFID tag(s) 100.

FIG. 54 is a flowchart illustrating a performance of step 310 in greaterdetail. This operation begins with a step 5402, where perforations aremade on tag substrate 116 between tags 100. These perforations enableusers to separate tags 100 for individual placement on various objects.

In step, 5404, each tag 100 is inspected to ensure proper assembly. Thisstep comprises ensuring proper placement of related electronics 106 anddie 104.

In step 5406, continuous roll(s) of tags 100 are cut and arranged intosheets.

In step 5408, an adhesive backing is applied to tag substrate 116. Thisadhesive backing is enables tags 100 to be attached to objects, such asbooks and consumer products.

3.0 Tag Assembly Apparatuses

The present invention is also directed to a tag assembly apparatus.FIGS. 55 and 56 are block diagrams of two tag assembly apparatuses thatemploy the techniques described herein.

3.1 “Pads Up” Assembly Apparatus

FIG. 55 illustrates a “pads up” assembly apparatus 5500. Assemblyapparatus 5500 assembles tags in a “pads up” manner, as describedherein. Thus, assembly apparatus 5500 performs the steps as describedherein with reference to FIGS. 3 and 11.

Assembly apparatus 5500 includes a support surface supplier 5502, asupport surface collector 5504, a wafer preparation module 5506, a firstdie transfer module 5508, a transfer surface supplier 5510, a transfersurface collector 5512, a second die transfer module 5514, a tagsubstrate supplier 5516, a post processing module 5518, an adhesiveapplication module 5520, and a printing module 5522.

Support surface supplier 5502 and support surface collector 5504 conveysupport surface 404 in a direction, as indicated by the arrows in FIG.55. These elements are spools. However, other suitable means ofconveyance can be used.

Wafer preparation module 5506 performs steps 304 and 306. Thus, waferpreparation module 5506 applies wafer 400 to support surface 404. Inaddition, wafer preparation module 5506 separates the plurality of dies104 on wafer 400. Wafer preparation module 5506 is implemented withsuitable mechanisms and scribing implements, such as laser(s).

First die transfer module 5508 transfers die(s) 104 from support surface404 to transfer surface 1202. That is, first die transfer module 5508performs step 1102. Accordingly, first die transfer module 5508 includespiston(s), roller(s), air jet(s), and/or punching devices. First dietransfer module 5508 may include an adhesive tape, a punch tape, amulti-barrel transport mechanism, and/or a die frame, and othercomponents associated with these components, such as are furtherdescribed above for die transfer. First die transfer module 5508 alsoincludes element(s) for releasing die(s) 104 from support surface 404,such as heating components and/or radiation devices.

Transfer surface supplier 5510 and transfer surface collector 5512convey transfer surface 1202 in a direction, as indicated by the arrowsin FIG. 55. These elements are spools. However, other suitable means ofconveyance can be used.

Second die transfer module 5514 transfers die(s) 104 from transfersurface 1202 to tag substrate 116. Thus, second die transfer module 5514performs step 1106. Accordingly, second die transfer module 5514includes piston(s), roller(s), air jet(s), and/or punching devices.Second die transfer module 5514 may include an adhesive tape, a punchtape, a multi-barrel transport mechanism, and/or a die frame, and othercomponents associated with these components, such as are furtherdescribed above for die transfer. Second die transfer module 5514 alsoincludes element(s) for releasing die(s) 104 from support surface 404,such as heating components and/or radiation devices.

Tag substrate supplier 5516 conveys tag substrate 116 towards postprocessing module 5518, as indicated by the arrows in FIG. 55. Tagsubstrate supplier 5516 includes roller(s). However, other suitablemeans of conveyance can be used.

Post processing module 5518 performs the post processing operationsdescribed herein with reference to step 310.

Adhesive application module 5520 applies adhesive to tag substrate 116,pursuant to step 1104. To perform this step, adhesive application module5520 includes a sprayer. However, adhesive application module 5520 canemploy other suitable devices to perform this step.

Printing and overcoating module 5522 prints related electronics 106 andapplies an overcoating onto tag substrate 116, pursuant to steps 1108and 1110. Thus, printing and overcoating module 5522 includes screenprinting component(s) and sprayer(s). However, printing and overcoatingmodule 5522 can employ other suitable devices, such as an ink jets,thermal spray equipment, and/or oblation devices.

3.2 “Pads Down” Assembly Apparatus

FIG. 56 illustrates a “pads down” assembly apparatus 5600. Assemblyapparatus 5600 assembles tags in a “pads down” manner, as describedherein. Thus, assembly apparatus performs the steps as described hereinwith reference to FIGS. 3 and 16.

Assembly apparatus 5600 includes a support surface supplier 5502, asupport surface collector 5504, a wafer preparation module 5506, a firstdie transfer module 5508, a first transfer surface supplier 5510, afirst transfer surface collector 5512, a second die transfer module5602, a second transfer surface supplier 5604, a second transfer surfacecollector 5606, a tag substrate supplier 5608, a third die transfermodule 5610, a post processing module 5556, an adhesive applicationmodule 5628, and a printing module 5626.

Support surface supplier 5502 and support surface: collector 5504 conveysupport surface 404 in a direction, as indicated by the arrows in FIG.56. These elements are spools. However, other suitable means ofconveyance can be used.

Wafer preparation module 5506 performs steps 304 and 306. Thus, waferpreparation module 5506 applies wafer 400 to support surface 404. Inaddition, wafer preparation module 5506 separates the plurality of dies104 on wafer 400. Wafer preparation module 5506 is implemented withsuitable mechanisms and scribing implements, such as laser(s).

First die transfer module 5508 transfers die(s) 104 from support surface404 to transfer surface 1202. That is, first die transfer module 5508performs step 1620. Accordingly, first die transfer module 5508 includespiston(s), roller(s), air jet(s), and/or punching devices. First dietransfer module 5508 may include an adhesive tape, a punch tape, amulti-barrel transport mechanism and/or process, and/or a die frame, andother components associated with these components, such as are furtherdescribed above for die transfer. First die transfer module 5508 alsoincludes element(s) for releasing die(s) 104 from support surface 404,such as heating components and/or radiation devices.

First transfer surface supplier 5510 and first transfer surfacecollector 5512 convey transfer surface 1202 in a direction, as indicatedby the arrows in FIG. 56. These elements are spools. However, othersuitable means of conveyance can be used.

Second die transfer module 5602 transfers die(s) 104 from transfersurface 1202 to secondary transfer surface 1202. Thus, second dietransfer module 5602 performs step 1622. Accordingly, second dietransfer module 5602 includes piston(s), roller(s), air jet(s), and/orpunching devices. Second die transfer module 5602 may include anadhesive tape, a punch tape, a multi-barrel transport mechanism and/orprocess, and/or a die frame, and other components associated with thesecomponents, such as are further described above for die transfer. Seconddie transfer module 5602 also includes element(s) for releasing die(s)104 from transfer surface 1202, such as heating components and/orradiation devices.

Second transfer surface supplier 5510 and second transfer surfacecollector 5512 convey secondary transfer surface 1202 in a direction, asindicated by the arrows in FIG. 56. These elements are spools. However,other suitable means of conveyance can be used.

Tag substrate supplier 5608 conveys tag substrate 116 towards postprocessing module 5556, as indicated by the arrows in FIG. 56. Tagsubstrate supplier 5608 includes roller(s). However, other suitablemeans of conveyance can be used.

Third die transfer module 5610 transfers die(s) 104 from secondarytransfer surface 1202 to tag substrate 116. Thus, third die transfermodule 5610 performs step 1608. Accordingly, third die transfer module5610 includes piston(s), roller(s), air jet(s), and/or punching devices.Third die transfer module 5610 may include an adhesive tape, a punchtape, a multi-barrel transport mechanism and/or process, and/or a dieframe, and other components associated with these components, such asare further described above for die transfer. Third die transfer module5610 also includes element(s) for releasing die(s) 104 from secondarytransfer surface 1202, such as heating components and/or radiationdevices.

Adhesive application module 5628 applies adhesive to tag substrate 116,pursuant to step 1606. To perform this step, adhesive application module5628 includes a sprayer. However, adhesive application module 5628 canemploy other suitable devices to perform this step.

Printing module 5626 prints related electronics 106, pursuant to step1606. Thus, printing module 5626 includes screen printing component(s)and sprayer(s). However, printing and overcoating module 5626 can employother suitable devices, such as an ink jets, thermal spray equipment,and/or oblation devices.

Post processing module 5556 performs the post processing operationsdescribed herein with reference to step 310.

Note that “pads down” assembly apparatus 5600, and other assemblyapparatuses described herein, may also be adapted to transfer diesdirectly from a support surface to a substrate, as would be understoodby persons skilled in the relevant art(s) from the teachings herein.

4.0 Conclusion

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample, and not limitation. It will be apparent to persons skilled inthe relevant arts that various changes in form and detail can be madetherein without departing from the spirit and scope of the invention.Thus the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

1-31. (canceled)
 32. A method for transferring dies to a surface,comprising: (a) filling a hollow barrel with a plurality of dies; and(b) depositing a die from the hollow barrel onto the surface.
 33. Themethod of claim 32, further comprising: (c) depositing dies from thehollow barrel onto the surface until the hollow barrel is depleted ofthe plurality of dies.
 34. A system for transferring dies to a surface,comprising: means for filling a hollow barrel with a plurality of dies;and means for depositing a die from the hollow barrel onto the surface.35. The system of claim 34, further comprising: means for depositingdies from the hollow barrel onto the surface until the hollow barrel isdepleted of the plurality of dies.